All Dovecot Settings

Settings

`@mailbox_defaults`

Default	[None]
Value	Groups Includes
Allowed Values	`english`
See Also	`mailbox_special_use`
Changes	Changed: 2.4.3 Changed default `mailbox_auto` value for the mailboxes from `no` to `subscribe`.

Group that expands to recommended English language mailbox names with mailbox_special_use flags added.

INFO

@mailbox_defaults = english

doveconf

  namespace inbox {
    inbox = yes
    mailbox Drafts {
      auto = subscribe
      special_use = \Drafts
    }
    mailbox Junk {
      auto = subscribe
      special_use = \Junk
    }
    mailbox Sent {
      auto = subscribe
      special_use = \Sent
    }
    mailbox Trash {
      auto = subscribe
      special_use = \Trash
    }
  }

`@metric_defaults`

Default	[None]
Value	Groups Includes
Allowed Values	`proxybackend`
See Also	`metric`

Group that expands to recommended metric settings in proxies or backends.

INFO

@metric_defaults = proxy

doveconf

  metric auth_successes {
    filter = event=auth_request_finished AND success=yes
  }
  metric auth_failures {
    filter = event=auth_request_finished AND NOT success=yes
  }
  metric login_aborted {
    filter = event=login_aborted
    group_by reason {
    }
  }
  metric proxy_session_established {
    filter = event=proxy_session_established
  }

@metric_defaults = backend

doveconf

  metric auth_successes {
    filter = event=auth_request_finished AND success=yes
  }
  metric auth_failures {
    filter = event=auth_request_finished AND NOT success=yes
  }
  metric imap_commands {
    filter = event=imap_command_finished
    group_by tagged_reply_state {
    }
  }
  metric mail_deliveries {
    filter = event=mail_delivery_finished
  }
  metric mail_submissions {
    filter = event=smtp_submit_finished
  }
  metric mail_user_session_finished {
    filter = event=mail_user_session_finished
    fields = rss utime
  }

`acl`

Value	Named Filter
See Also	`acl_id` `acl_rights`
Plugin	acl plugin
Changes	Added: 2.4.0

Specifies an ACL entry on global, namespace or mailbox level. The filter name refers to the acl_id setting.

Has two settings:

acl_id: The identifier in ACL.
acl_rights: The permission to grant - or deny - for this user.

`acl_cache_ttl`

Default	`30s`
Value	time
Plugin	acl plugin

How long to cache the ACLs read from dovecot-acl files. Set to 0 to re-read the files on every lookup.

`acl_defaults_from_inbox`

Default	`no`
Value	boolean
Plugin	acl plugin

If enabled, the default ACLs for private and shared namespaces (but not public namespaces) are taken from the INBOX. This means that giving somebody access to your INBOX will give them access to all your other mailboxes as well, unless the specific mailboxes' ACLs override the INBOX's.

`acl_dict_index`

Default	`no`
Value	boolean
Plugin	acl plugin
Changes	Added: 2.4.2

Should ACL dict updates assume that there is a reverse lookup index. This should be used with SQL/CQL based dicts.

`acl_driver`

Default	[None]
Value	string
Plugin	acl plugin
Changes	Added: 2.4.0

The ACL driver to use. This setting is REQUIRED - if empty, the acl plugin is disabled.

Currently, there is a single driver available: vfile. This driver supports two ways of defining the ACL configuration:

global: ACL rules are applied to all users.
per-mailbox: Each mailbox has separate ACL rules. They are stored in a dovecot-acl file in each mailbox (or mail_control_path) directory. This is the default.

`acl_global_path`

Default	[None]
Value	string
See Also	`acl`
Plugin	acl plugin
Changes	Removed: 2.4.3

Location of global ACL configuration file. This option is deprecated, you should use acl instead.

`acl_globals_only`

Default	`no`
Value	boolean
Plugin	acl plugin

If enabled, don't try to find dovecot-acl files from mailbox directories. This reduces unnecessary disk I/O when only global ACLs are used.

`acl_groups`

Default	[None]
Value	string
Plugin	acl plugin

A comma-separated string which contains all the groups the user belongs to.

A user's UNIX groups have no effect on ACLs (you can enable them by using a special post-login scripting.

The default ACL for mailboxes is to give the mailbox owner all permissions and other users none. Mailboxes in public namespaces don't have owners, so by default no one can access them.

`acl_id`

Default	[None]
Value	string
See Also	`acl` ACL File Format
Plugin	acl plugin
Changes	Added: 2.4.0

Specifies identity to match. See ACL File Format for values. The acl filter name refers to this setting.

`acl_ignore`

Default	`no`
Value	boolean
Plugin	acl plugin
Changes	Added: 2.4.0

Can be used in global config, namespace, or mailbox level to ignore ACLs.

namespace ignore {
  acl_ignore = yes
}

`acl_rights`

Default	[None]
Value	string
See Also	`acl` ACL File Format
Plugin	acl plugin
Changes	Added: 2.4.0

Specifies rights for this acl. See ACL File Format for values. This is usually used in acl block.

`acl_sharing_map`

Value	Named Filter
See Also	dictionary
Plugin	acl plugin
Changes	Added: 2.4.0

A shared mailbox dictionary that defines which users may LIST mailboxes shared by other users.

Not every dictionary driver is supported here. The map needs dict_iterate which is not supported by redis and ldap.

See shared mailbox listing for further details on the contents of the dictionary entries.

Example:

acl_sharing_map {
  dict file {
    path = /var/lib/dovecot/shared-mailboxes
  }
}

`acl_user`

Default	[None]
Value	string
See Also	ACL Master Users
Plugin	acl plugin

See auth_master_user_separator for the format of this setting.

`apparmor_hats`

Default	[None]
Value	Boolean List
Plugin	apparmor plugin

List of AppArmor "hats" to change to when a user is loaded.

Example:

apparmor_hats {
  hat_name = yes
  another_hat = yes
}

`auth_allow_cleartext`

Default	`no`
Value	boolean
Changes	Added: 2.4.0

If no, disables the LOGIN command and all other cleartext authentication unless SSL/TLS is used (LOGINDISABLED capability) or the connection is secured (see ssl).

See SSL configuration for more detailed explanation of how this setting interacts with the ssl setting.

This setting replaces the disable_plaintext_auth setting.

`auth_allow_weak_schemes`

Default	`no`
Value	boolean
Changes	Added: 2.4.0

Controls whether password schemes marked as weak are allowed to be used. See Password Schemes for disabled by default schemes.

If enabled, will emit warning to logs. If a disabled scheme is used, an error is logged.

Notably, any explicitly cleartext schemes (such as PLAIN), CRAM-MD5, and DIGEST-MD5 are not affected by this setting.

`auth_anonymous_username`

Default	`anonymous`
Value	string

This specifies the username to be used for users logging in with the ANONYMOUS SASL mechanism.

`auth_cache_negative_ttl`

Default	`1hour`
Value	time

This sets the time to live for negative hits to passdb or userdb (i.e., when the user is not found or there is a password mismatch).

The value 0 completely disables caching of these hits.

`auth_cache_size`

Default	[None]
Value	size

The authentication cache size (e.g., 10M).

auth_cache_size = 0 disables use of the authentication cache.

A typical passdb cache entry is around 50 bytes and a typical userdb cache entry is around 100-200 bytes, depending on the amount of information your user and password database lookups return.

`auth_cache_ttl`

Default	`1hour`
Value	time

Time to live for cache entries.

After the TTL expires, the cached record is no longer used, unless the main database look-up returns internal failure.

Entries are removed from the cache only when the cache is full and a new entry is to be added.

`auth_cache_verify_password_with_worker`

Default	`no`
Value	boolean

The auth master process by default is responsible for the hash verifications. Setting this to yes moves the verification to auth-worker processes. This allows distributing the hash calculations to multiple CPU cores, which could make sense if strong hashes are used.

`auth_debug`

Default	`no`
Value	boolean
Changes	Deprecated: 2.4.0 The setting is obsolete, and kept only for backwards compatibility. Use `log_debug = category=auth` instead.

Enables all authentication debug logging (also enables auth_verbose).

Passwords are logged as <hidden>.

`auth_debug_passwords`

Default	`no`
Value	boolean

This setting adjusts log verbosity. In the event of password mismatches, the passwords and the scheme used are logged so that the problem can be debugged.

Note: You also need to enable log_debug = category=auth.

`auth_default_domain`

Default	`no`
Value	boolean
Changes	Added: 2.4.0

This setting indicates the default realm/domain to use if none has been specified. The setting is used for both SASL realms and appending an @domain element to the username in cleartext logins.

`auth_failure_delay`

Default	`2secs`
Value	time
See Also	`auth_internal_failure_delay`

This is the delay before replying to failed authentication attempts. Using passdb: nodelay Extra Field bypasses this setting.

This setting defines the interval for which the authentication process flushes all auth failures. Thus, this is the maximum interval a user may encounter. However, there can be additional delays added by Authentication Penalty.

This setting doesn't affect internal failures. See auth_internal_failure_delay.

`auth_gssapi_hostname`

Default	`<name returned by gethostname()>`
Value	string

This supplies the hostname to use in Generic Security Services API (GSSAPI) principal names.

Use "$ALL" (with the quotation marks) to allow all keytab entries.

`auth_internal_failure_delay`

Default	`2secs`
Value	time (milliseconds)
See Also	`auth_failure_delay`
Changes	Added: 2.4.0

The delay before replying to client when authentication fails with internal failure. An additional 0..50% delay is added on top of this to prevent thundering herd issues.

This setting is intended to prevent clients from hammering the server with immediate retries.

`auth_krb5_keytab`

Default	`<system default (e.g. /etc/krb5.keytab)>`
Value	string

This specifies the Kerberos keytab to use for the GSSAPI mechanism.

Note: You may need to set the auth service to run as root in order for this file to be readable.

`auth_master_user_separator`

Default	[None]
Value	string

The separator to use to enable master users to login by specifying the master username within the normal username string (i.e., not using the SASL mechanism's master support).

Example:

# Allows master login of the format <username>*<masteruser>
# E.g. if user = foo, and master_user = muser,
#	login username = foo*muser
auth_master_user_separator = *

`auth_mechanisms`

Default	`plain`
Value	Boolean List
See Also	authentication mechanisms

Here you can supply a space-separated list of the authentication mechanisms you wish to use.

Example:

auth_mechanisms = plain login

`auth_policy`

Value	Named Filter
See Also	Authentication Policy
Changes	Added: 2.4.0

Filter for auth policy specific settings.

`auth_policy_check_after_auth`

Default	`yes`
Value	boolean
See Also	`auth_policy_server_url`

Do policy lookup after authentication is completed?

`auth_policy_check_before_auth`

Default	`yes`
Value	boolean
See Also	`auth_policy_server_url`

Do policy lookup before authentication is started?

`auth_policy_hash_mech`

Default	`sha256`
Value	string
Allowed Values	`md4md5sha1sha256sha512`
See Also	`auth_policy_server_url`

Hash mechanism to use for password.

`auth_policy_hash_nonce`

Default	[None]
Value	string
See Also	`auth_policy_server_url`

Cluster-wide nonce to add to hash.

This should contain a secret randomly generated string, which is the same for each Dovecot server within the cluster.

REQUIRED configuration when you want to use authentication policy.

Example:

auth_policy_hash_nonce = <localized_random_string>

`auth_policy_log_only`

Default	`no`
Value	boolean
See Also	`auth_policy_server_url`

Only log what the policy server response would do?

If yes, no request is made to the policy server.

`auth_policy_reject_on_fail`

Default	`no`
Value	boolean
See Also	`auth_policy_server_url`

If policy request fails for some reason, should users be rejected?

`auth_policy_report_after_auth`

Default	`yes`
Value	boolean

Report authentication result?

If no, there will be no report for the authentication result.

`auth_policy_request_attributes`

Default	`login=%{requested_username} pwhash=%{hashed_password} remote=%{remote_ip} device_id=%{client_id} protocol=%{protocol} session_id=%{session} fail_type=%{fail_type}`
Value	String List
See Also	`auth_policy_server_url`
Changes	Changed: 2.4.0 Default has changed.

Request attributes specification.

See Auth Policy Variables for variables that can be used for this setting.

`auth_policy_server_api_header`

Default	[None]
Value	string
See Also	`auth_policy_server_url`

Header and value to add to request (for API authentication).

Note: See https://en.wikipedia.org/wiki/Basic_access_authentication#Client_side

This can be used when you are using the weakforced policy server and the web listener password is "super":

$ echo -n wforce:super | base64
d2ZvcmNlOnN1cGVy

Then the correct value for this setting is:

auth_policy_server_api_header = Authorization: Basic d2ZvcmNlOnN1cGVy

`auth_policy_server_url`

Default	[None]
Value	URL

URL of the policy server.

URL is appended with ?command=allow/report. If URL ends with &, the ? is not appended.

REQUIRED configuration when you want to use authentication policy.

Example:

auth_policy_server_url = http://example.com:4001/

`auth_realms`

Default	[None]
Value	Boolean List

This setting supplies a list of realms for those SASL authentication mechanisms that need them. Realms are an integral part of Digest-MD5.

You will need to specify realms you want to advertise to the client in the config file:

Example:

auth_realms = example.com another.example.com foo

`auth_ssl_require_client_cert`

Default	`no`
Value	boolean
See Also	`ssl_server_ca_file` `ssl_server_request_client_cert` SSL configuration

If yes, authentication fails when a valid SSL client certificate is not provided.

`auth_ssl_username_from_cert`

Default	`no`
Value	boolean
See Also	`ssl_server_cert_username_field`

Setting to yes indicates that the username should be taken from the client's SSL certificate.

Generally, this will be either commonName or x500UniqueIdentifier.

The text is looked up from subject DN's specified field using OpenSSL's X509_NAME_get_text_by_NID() function. By default the CommonName field is used. You can change the field with ssl_server_cert_username_field = name setting (parsed using OpenSSL's OBJ_txt2nid() function).

x500UniqueIdentifier is a common choice.

`auth_use_winbind`

Default	`no`
Value	boolean

By default, the NTLM mechanism is handled internally.

If yes, perform NTLM and GSS-SPNEGO authentication with Samba's winbind daemon and ntlm_auth helper.

This option is useful when you need to authenticate users against a Windows domain (either AD or NT).

`auth_username_chars`

Default	`abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ01234567890.-_@`
Value	string

The list of the characters allowed in a username.

If the user-supplied username contains a character not listed here, login automatically fails.

This is an additional check to make sure the user can't exploit any quote-escaping vulnerabilities that may be connected with SQL/LDAP databases.

If you want to allow all characters, leave the value empty.

`auth_username_format`

Default	`%{user \| lower}`
Value	string

When this setting is used globally, it changes the username, including %{user} variable, for all passdb and userdb lookups.

This setting can also be used in passdb/userdb passwd_file { auth_username_format } to change the username for the duration of the lookup. The %{user} variable is not changed. If used inside other passdbs/userdbs the setting is ignored.

You can use the standard variables here.

Examples:

%{user | lower}: Lowercases the username
%{user | username}: Drops the domain if one was supplied
%{user | username}-AT-%{user | domain}: Changes the "@" symbol into "-AT-" before lookup

This translation is done after the changes specified with the auth_username_translation setting.

`auth_verbose`

Default	`no`
Value	boolean

Adjust log verbosity.

If yes, log unsuccessful authentication attempts and why they failed.

`auth_verbose_passwords`

Default	`no`
Value	string
Allowed Values	`noyesplainsha1`

In case of password mismatches, log the attempted password. You can also truncate the logged password to n chars by appending :n (e.g. sha1:6).

Available transformations:

plain, yes: Output cleartext password (NOT RECOMMENDED)
sha1: Output SHA1 hashed password

`auth_winbind_helper_path`

Default	[None]
Value	string

This setting tells the system the path for Samba's ntlm_auth helper binary.

Example:

auth_winbind_helper_path = /usr/bin/ntlm_auth

`cassandra_application_name`

Default	`Dovecot`
Value	string
See Also	`cassandra_application_version` `cassandra_client_id`
Changes	Added: 2.4.6

Application name sent to the Cassandra server when connecting. This can be used to identify Dovecot's client connections on the Cassandra side.

If empty, neither the application name nor cassandra_application_version is sent.

Older cpp-driver versions can't send the application name. The default is then empty, and setting a name fails.

`cassandra_application_version`

Default	`[Dovecot version]`
Value	string
See Also	`cassandra_application_name`
Changes	Added: 2.4.6

Application version sent to the Cassandra server when connecting. If empty, the Dovecot version is used.

This is sent only when cassandra_application_name is non-empty.

`cassandra_client_id`

Default	`[random UUID]`
Value	string
See Also	`cassandra_application_name`
Changes	Added: 2.4.6

Client ID UUID sent to the Cassandra server when connecting, e.g. 01234567-89ab-4def-8123-456789abcdef. If empty, the driver generates a random UUIDv4.

`cassandra_connect_timeout`

Default	`5s`
Value	time (milliseconds)

Connection timeout.

`cassandra_connections_per_host`

Default	`1`
Value	unsigned integer
See Also	`cassandra_io_thread_count`
Changes	Added: 2.4.6

Number of connections to create to each Cassandra host for each IO thread. The total number of connections per host is this value multiplied by cassandra_io_thread_count.

Increasing this may help to increase concurrency with busy processes. Must not be 0.

`cassandra_debug_queries`

Default	`no`
Value	boolean

Whether to log CQL queries.

`cassandra_delete_consistency`

Default	`local-quorum`
Value	string
Allowed Values	`anylocal-serialserialonetwothreelocal-quorumquorumeach-quorumall`
See Also	Cassandra: Consistency

Write consistency when deleting from the database. See Cassandra: Consistency.

`cassandra_delete_fallback_consistency`

Default	`cassandra_delete_consistency`
Value	string
Allowed Values	`anylocal-serialserialonetwothreelocal-quorumquorumeach-quorumall`
See Also	Cassandra: Consistency

Write consistency when deleting from the database fails with primary consistency.

`cassandra_execution_retry_interval`

Default	[None]
Value	time (milliseconds)

If the driver supports speculative execution policy, configures constant speculative execution policy. See https://docs.datastax.com/en/developer/java-driver/latest/manual/core/speculative_execution/index.html

WARNING

If Cassandra is completely unavailable and speculative execution is used, Cassandra cpp-driver library starts hanging all queries due to a bug. This may cause problems in the dict process even after Cassandra is back online. When this happens, "Dict server timeout" errors are being logged.

`cassandra_execution_retry_times`

Default	[None]
Value	time (milliseconds)

WARNING

`cassandra_fallback_failure_threshold`

Default	`3`
Value	unsigned integer
See Also	`cassandra_fallback_window` Cassandra: Fallback Consistency
Changes	Added: 2.4.6

Number of consecutive queries that must fail with the primary consistency within cassandra_fallback_window before all the following queries of the same type are sent with the fallback consistency. A query that succeeds with the primary consistency resets the count. A single failing query is always retried with the fallback consistency. Must not be 0.

Setting this to 1 together with cassandra_primary_retry_count = 0 restores the behavior of older versions, where a single failure switched to the fallback consistency.

See Cassandra: Fallback Consistency.

`cassandra_fallback_window`

Default	`5s`
Value	time (milliseconds)
See Also	`cassandra_fallback_failure_threshold` Cassandra: Fallback Consistency
Changes	Added: 2.4.6

Time window for counting the consecutive failures for cassandra_fallback_failure_threshold. Must not be 0.

A failure is counted only when the query finishes. A query that times out on the client side finishes only after cassandra_request_timeout, so such timeouts reach the threshold only if enough queries are running concurrently.

See Cassandra: Fallback Consistency.

`cassandra_heartbeat_interval`

Default	`30s`
Value	time

How often to send keepalive packets to cassandra nodes.

`cassandra_hosts`

Default	[None]
Value	Boolean List

List of hosts or IP addresses to connect.

`cassandra_idle_timeout`

Default	`0`
Value	time (milliseconds)

How long to idle before disconnecting.

`cassandra_io_thread_count`

Default	`[driver dependent]`
Value	unsigned integer

Set number of IO threads to handle query requests.

`cassandra_keyspace`

Default	[None]
Value	string

Specifies the keyspace name to use.

`cassandra_latency_aware_exclusion_threshold`

Default	`2.0`
Value	string
See Also	`cassandra_latency_aware_routing`
Changes	Added: 2.4.6

Used by cassandra_latency_aware_routing: how much worse a host's average latency may be compared to the best performing host before it is penalized. For example the default 2.0 penalizes hosts whose average latency is more than twice the best host's latency.

This is a floating point number, which must be at least 1.0.

`cassandra_latency_aware_min_measured`

Default	`50`
Value	unsigned integer
See Also	`cassandra_latency_aware_routing`
Changes	Added: 2.4.6

Used by cassandra_latency_aware_routing: minimum number of latency measurements per host before the host's latency is taken into account.

`cassandra_latency_aware_retry_period`

Default	`10s`
Value	time (milliseconds)
See Also	`cassandra_latency_aware_routing`
Changes	Added: 2.4.6

Used by cassandra_latency_aware_routing: how long a host is penalized before it is given another chance.

`cassandra_latency_aware_routing`

Default	`no`
Value	boolean
See Also	`cassandra_latency_aware_exclusion_threshold` `cassandra_latency_aware_min_measured` `cassandra_latency_aware_retry_period` `cassandra_latency_aware_scale` `cassandra_latency_aware_update_rate`

When turned on, latency-aware routing tracks the latency of queries to avoid sending new queries to poorly performing Cassandra nodes.

`cassandra_latency_aware_scale`

Default	`100ms`
Value	time (milliseconds)
See Also	`cassandra_latency_aware_routing`
Changes	Added: 2.4.6

Used by cassandra_latency_aware_routing: controls the weight given to older latencies when calculating a host's average latency. A larger value gives more weight to older measurements.

`cassandra_latency_aware_update_rate`

Default	`100ms`
Value	time (milliseconds)
See Also	`cassandra_latency_aware_routing`
Changes	Added: 2.4.6

Used by cassandra_latency_aware_routing: how often the best average latency is recalculated.

`cassandra_local_datacenter`

Default	[None]
Value	string
See Also	`cassandra_hosts` `cassandra_read_consistency` `cassandra_write_consistency` `cassandra_delete_consistency`
Changes	Added: 2.4.6

Name of the local datacenter. Queries are sent only to the hosts in the local datacenter. This also defines the datacenter used by the local-one and local-quorum consistency levels.

If empty, the driver uses the datacenter of whichever contact point in cassandra_hosts answers first. This is nondeterministic when cassandra_hosts contains hosts from multiple datacenters. Hosts in the other datacenters are never used. It's recommended to set this when the Cassandra cluster has multiple datacenters. See Cassandra: Local Datacenter.

`cassandra_log_level`

Default	`warn`
Value	string
Allowed Values	`criticalerrorwarninfodebugtrace`

Driver log level.

`cassandra_log_retries`

Default	`no`
Value	boolean

Whether to log about failed requests that are retried (which may or may not succeed after the retry).

`cassandra_logged_batches`

Default	`yes`
Value	boolean
Changes	Added: 2.4.6

Whether transactions with multiple statements are sent as LOGGED batches. When no, they are sent as UNLOGGED batches. This is needed for Cassandra-compatible databases that don't support LOGGED batches.

UNLOGGED batches that update multiple partitions aren't atomic: if the batch fails, only some of the changes may have been written. Batches that update a single partition are atomic in either case.

`cassandra_metrics_path`

Default	[None]
Value	string

Path where to write JSON metrics. See Cassandra: Metrics.

`cassandra_page_size`

Default	[None]
Value	unsigned integer

When a query returns many rows, it can be sometimes inefficient to return them as a single response message. Instead, the driver can break the results into pages which get returned as they are needed.

This setting controls the size of each page.

Set to 0 to disable.

`cassandra_password`

Default	[None]
Value	string

Password for authentication.

`cassandra_port`

Default	`9042`
Value	Port Number

CQL port to use.

`cassandra_primary_retry_count`

Default	`2`
Value	unsigned integer
See Also	Cassandra: Fallback Consistency
Changes	Added: 2.4.6

How many times a query that failed with a likely transient error (e.g. a timeout reported by the Cassandra server) is retried with the primary consistency before it's retried with the fallback consistency. 0 disables these retries.

The primary consistency retries are skipped, and the failed query is retried immediately with the fallback consistency, if:

Cassandra reports that there aren't enough replicas available,
no hosts are available,
the query timed out on the client side after cassandra_request_timeout, or
the queries have already been switched to the fallback consistency because of cassandra_fallback_failure_threshold.

See Cassandra: Fallback Consistency.

`cassandra_protocol_version`

Default	`depends on driver version`
Value	string
Allowed Values	`345`

Cassandra protocol version to use. It is good idea to specify this to avoid warnings about version handshake if the driver supports a higher protocol version than the server.

INFO

If you want to use server-side prepared statements, you need to use at least 4.

`cassandra_read_consistency`

Default	`local-quorum`
Value	string
Allowed Values	`anylocal-serialserialonetwothreelocal-quorumquorumeach-quorumall`
See Also	Cassandra: Consistency

Read consistency.

`cassandra_read_fallback_consistency`

Default	`cassandra_read_consistency`
Value	string
Allowed Values	`anylocal-serialserialonetwothreelocal-quorumquorumeach-quorumall`
See Also	Cassandra: Consistency

Read consistency if primary consistency fails.

`cassandra_reconnect_base_delay`

Default	`2s`
Value	time (milliseconds)
See Also	`cassandra_reconnect_policy` `cassandra_reconnect_max_delay`
Changes	Added: 2.4.6

With cassandra_reconnect_policy = exponential this is the initial delay before reconnecting to a Cassandra host. It must be larger than 1 millisecond.

With cassandra_reconnect_policy = constant this is the delay between all reconnection attempts. 0 means reconnecting immediately.

`cassandra_reconnect_max_delay`

Default	`60s`
Value	time (milliseconds)
See Also	`cassandra_reconnect_policy` `cassandra_reconnect_base_delay`
Changes	Added: 2.4.6

With cassandra_reconnect_policy = exponential this is the maximum delay between reconnection attempts. It must not be smaller than cassandra_reconnect_base_delay.

Not used with cassandra_reconnect_policy = constant.

`cassandra_reconnect_policy`

Default	`exponential`
Value	string
Allowed Values	`exponentialconstant`
See Also	`cassandra_reconnect_base_delay` `cassandra_reconnect_max_delay`
Changes	Added: 2.4.6

How to reconnect to a Cassandra host after the connection is lost:

exponential: Start with cassandra_reconnect_base_delay and increase the delay exponentially after each attempt, up to cassandra_reconnect_max_delay. A random jitter of +/- 15% is added to the delay.
constant: Always wait cassandra_reconnect_base_delay.

cpp-driver older than v2.14 supports only constant, which is then also the default.

`cassandra_request_queue_size`

Default	`8192`
Value	unsigned integer
See Also	`cassandra_io_thread_count` `cassandra_metrics_path`
Changes	Added: 2.4.6

Maximum number of requests queued for each IO thread while waiting for the thread to process them. The total capacity is this value multiplied by cassandra_io_thread_count. The driver rounds the value up to the next power of two.

When the queue is full, new requests fail immediately. These failures are counted in the recv_err_queue_full field of cassandra_metrics_path. Must not be 0.

`cassandra_request_timeout`

Default	`60s`
Value	time (milliseconds)

How long to wait for a query to finish.

`cassandra_source_ip`

Default	[None]
Value	string
Changes	Added: 2.4.6

Source IP address to use for connections to Cassandra hosts. Only IP addresses are supported, not host names. If empty, the source IP address is chosen by the operating system.

`cassandra_ssl`

Default	`no`
Value	string
Allowed Values	`nocert-onlycert-ip`
See Also	SSL configuration `ssl_client_require_valid_cert`

Whether to use SSL when connecting to Cassandra, and how to verify the certificate:

no: Don't use SSL
cert-only: Verify the certificate, but not the IP address or host name.
cert-ip: Verify the certificate, and require IP address to match the certificate's common name or one of its subject alternative names.

You can also skip certificate validation by setting ssl_client_require_valid_cert = yes. The cassandra_ssl setting value must something else than no.

Configure SSL certificates using the ssl_client_* settings. See SSL configuration.

`cassandra_tcp_keepalive`

Default	[None]
Value	time
See Also	`cassandra_heartbeat_interval`
Changes	Added: 2.4.6

If non-zero, enable TCP keepalive for Cassandra connections with this initial delay. This can detect connections that have been silently dropped by e.g. firewalls or NAT devices. 0 disables TCP keepalive.

`cassandra_token_aware_routing`

Default	`yes`
Value	boolean
See Also	`cassandra_token_aware_shuffle_replicas`
Changes	Added: 2.4.6

Send queries directly to a host that has the data (a replica for the queried partition), avoiding an extra hop through a coordinator host. This should normally be kept enabled, but disabling it may be useful for debugging.

`cassandra_token_aware_shuffle_replicas`

Default	`yes`
Value	boolean
See Also	`cassandra_token_aware_routing`
Changes	Added: 2.4.6

Used by cassandra_token_aware_routing: randomly shuffle the replicas for each query. This distributes load better between the replicas, but reduces the effectiveness of the Cassandra server's caching. Disabling this may improve performance when the same keys are read repeatedly.

Older cpp-driver versions don't support shuffling. The default is then no, and enabling it fails.

`cassandra_user`

Default	[None]
Value	string

Username for authentication.

`cassandra_warn_timeout`

Default	`5s`
Value	time (milliseconds)

Emit warning if query takes longer than this.

`cassandra_write_consistency`

Default	`local-quorum`
Value	string
Allowed Values	`anylocal-serialserialonetwothreelocal-quorumquorumeach-quorumall`
See Also	Cassandra: Consistency

Write consistency when updating or inserting to the database.

`cassandra_write_fallback_consistency`

Default	`cassandra_write_consistency`
Value	string
Allowed Values	`anylocal-serialserialonetwothreelocal-quorumquorumeach-quorumall`
See Also	Cassandra: Consistency

Write consistency when updating or inserting to the database fails with primary consistency.

`cdb_path`

Default	[None]
Value	string

Path to the CDB database file.

`charset_aliases`

Default	[None]
Value	String List
Plugin	charset-alias plugin

List of <from>=<to> charsets. The "from" charsets will be treated as "to" charsets when decoding to UTF-8.

Example:

charset_aliases {
  shift_jis = sjis-win
  euc-jp = eucjp-win
  iso-2022-jp = iso-2022-jp-3
}

`compress_bz2_block_size_100k`

Default	`9`
Value	unsigned integer
Plugin	mail-compress plugin

The compression block size to use. Must be between 1 (100 000 bytes) and 9 (900 000 bytes).

`compress_deflate_level`

Default	`6`
Value	unsigned integer
Plugin	mail-compress plugin

The compression level to use for deflate compression. Must be between 0 (no compression) and 9.

`compress_gz_level`

Default	`6`
Value	unsigned integer
Plugin	mail-compress plugin

The compression level to use for gz compression. Must be between 0 (no compression) and 9.

`compress_zstd_level`

Default	`3`
Value	unsigned integer
Plugin	mail-compress plugin

The compression level to use for zstd compression. Must be between 1 and 22.

`crypt_acl_require_secure_key_sharing`

Default	`no`
Value	boolean
Plugin	mail-crypt plugin

If enabled, you cannot share a key to groups or someone without a public key.

`crypt_global_private_key`

Default	[None]
Value	Named List Filter
See Also	`crypt_private_key_file` `crypt_private_key_password`
Plugin	mail-crypt plugin

List of global private key(s) to decrypt mails. Add crypt_private_key_file and optionally crypt_private_key_password inside each filter.

`crypt_global_public_key_file`

Default	[None]
Value	File
Plugin	mail-crypt plugin

Public key to encrypt files. Key must be in PEM pkey format. The PEM key may additionally be base64-encoded into a single line, which can make it easier to store into userdb extra fields.

`crypt_private_key_file`

Default	[None]
Value	File
See Also	Mail Crypt Plugin: Converting EC key to PKEY `crypt_global_private_key` `crypt_user_key_encryption_key`
Plugin	mail-crypt plugin

Private key in Mail Crypt Plugin: Converting EC key to PKEY. The PEM key may additionally be base64-encoded into a single line, which can make it easier to store into userdb extra fields.

Used inside crypt_global_private_key and crypt_user_key_encryption_key lists.

`crypt_private_key_name`

Default	[None]
Value	string
See Also	`crypt_global_private_key` `crypt_user_key_encryption_key`
Plugin	mail-crypt plugin

Name of the private key inside crypt_global_private_key or crypt_user_key_encryption_key.

`crypt_private_key_password`

Default	[None]
Value	string
See Also	`crypt_private_key_file`
Plugin	mail-crypt plugin

Password to decrypt crypt_private_key_file.

`crypt_user_key_curve`

Default	[None]
Value	string
Plugin	mail-crypt plugin

Defines the elliptic curve to use for key generation. A key pair is generated for the user, and a key pair is generated for each folder. The folder key is encrypted using the user key.

This must be set if you wish to use folder keys rather than global keys. With global keys (either RSA or EC keys), all keying material is taken from the global key settings and no key generation is performed.

Any valid curve supported by the underlying cryptographic library is allowed.

Example:

crypt_user_key_curve = secp521r1

For EdDSA, you need to use X448 or X25519, case sensitive.

`crypt_user_key_encryption_key`

Default	[None]
Value	Named List Filter
See Also	`crypt_private_key_file` `crypt_private_key_password`
Plugin	mail-crypt plugin

List of private key(s) to decrypt user's master private key. Add crypt_private_key_file and optionally crypt_private_key_password inside each filter.

`crypt_user_key_password`

Default	[None]
Value	string
Plugin	mail-crypt plugin

Password to decrypt user's master private key.

`crypt_user_key_require_encrypted`

Default	`no`
Value	boolean
See Also	`crypt_user_key_password` `crypt_user_key_encryption_key`
Plugin	mail-crypt plugin

If yes, require user's master private key to be encrypted with crypt_user_key_password or crypt_user_key_encryption_key. If they are unset new user key generation will fail. This setting doesn't affect already existing non-encrypted keys.

`crypt_write_algorithm`

Default	`aes-256-gcm-sha256`
Value	string
Plugin	mail-crypt plugin

Set the encryption algorithm for newly written mails. If empty, new mails are not encrypted. Existing encrypted mails (with any algorithm) can be decrypted regardless of this setting.

`debug_log_path`

Default	`info_log_path`
Value	string

The log file to use for debug messages.

`default_client_limit`

Default	`1000`
Value	unsigned integer

Default value for service_client_limit, if not overridden by service-specific configuration.

`default_idle_kill_interval`

Default	`1 min`
Value	time

Default value for service_idle_kill_interval, if not overridden by service-specific configuration.

`default_internal_group`

Default	`dovecot`
Value	string
See Also	`default_internal_user` `mail_access_groups`

Define the default internal group. The mail_access_groups uses this as the default for giving mail processes UNIX socket access to various services. For proper security, no files or directories should be made writable for this group.

`default_internal_user`

Default	`dovecot`
Value	string
See Also	`default_internal_group`

Define the default internal user.

Unprivileged processes run under the ID of the internal user. This user should be distinct from the login user, to prevent login processes from disturbing other processes.

`default_login_user`

Default	`dovenull`
Value	string

The user the login process should run as.

This is the least trusted user in Dovecot: this user should not have access to anything at all.

`default_process_limit`

Default	`100`
Value	unsigned integer

Default value for service_process_limit, if not overridden by service-specific configuration.

`default_vsz_limit`

Default	`256 M`
Value	size

Default value for service_vsz_limit, if not overridden by service-specific configuration.

`deliver_log_format`

Default	`msgid=%{msgid}: %{message}`
Value	String without variables

The format to use for logging mail deliveries.

Variables that can be used for this setting (see Global variables):

Variable Name	Description
`%{message}`	Delivery status message (e.g., saved to INBOX)
`%{msgid}`
`%{subject}`	Subject
`%{from}`	From address
`%{from_envelope}`	SMTP FROM envelope
`%{size}`	Physical size
`%{vsize}`	Virtual size
`%{to_envelope}`	RCPT TO envelope
`%{delivery_time}`	How many milliseconds to deliver the mail
`%{session_time}`	LMTP session duration, not including `%{delivery_time}`
`%{storage_id}`	Backend-specific ID for mail, e.g. Maildir filename

Example:

deliver_log_format = stime=%{session_time} msgid=%{msgid}: %{message}

`dict`

Default	[None]
Value	Named List Filter
See Also	`dict_name` `dict_driver`

Creates a new dict. The filter name refers to the dict_name setting.

Example:

dict file {
  # ...
}

Since an empty dict_driver defaults to dict_name, there is no need to specify the dict_driver setting explicitly.

`dict_driver`

Default	`<dict_name>`
Value	string

The dict driver to use. Defaults to dict_name.

`dict_file_path`

Default	[None]
Value	string

Path for the dictionary file.

`dict_map`

Default	[None]
Value	Named List Filter
See Also	`dict_map_pattern`

Creates a new dict mapping. The filter name refers to the dict_map_pattern setting.

`dict_map_expire_field`

Default	[None]
Value	string

Field in the SQL table to use for tracking dict key expiration. This field is optional if no expiration is used by the code accessing the dict map.

`dict_map_key_field`

Default	[None]
Value	Named List Filter
See Also	`dict_map_pattern`

Creates a new field for the dict map. The filter name refers to the dict_map_key_field_value setting. The fields are part of the SQL query looking up the dict key.

`dict_map_key_field_name`

Default	[None]
Value	string
See Also	`dict_map_key_field`

Field in the SQL table to use for the dict_map_key_field.

`dict_map_key_field_type`

Default	`string`
Value	string
Allowed Values	`stringintuintdoublehexblobuuid`
See Also	`dict_map_key_field`

Type of the field in the SQL table for the dict_map_key_field.

`dict_map_key_field_value`

Default	[None]
Value	string
See Also	`dict_map_pattern` `dict_map_key_field`

Variable in the dict_map_pattern that maps to this dict_map_key_field. The value must always begin with $.

`dict_map_ldap_filter`

Default	[None]
Value	string

The ldap filter to use to find the ldap entry.

This setting is required for ldap dict_map

`dict_map_pattern`

Default	[None]
Value	string

Pattern that is matched to the accessed dict keys. The dict_map filter name refers to this setting. If the pattern matches the key, this dict map (and no other) is used. The dict maps are processed in the order listed in the configuration file.

`dict_map_sql_table`

Default	[None]
Value	string

SQL table to use for accessing this dict map.

`dict_map_username_field`

Default	[None]
Value	string

Field in the SQL table to use for accessing private dict keys in this dict map. This setting is optional if only shared keys are accessed.

`dict_map_value_field`

Default	[None]
Value	Named List Filter
See Also	`dict_map_value_field_name`

sql: Creates a new value for the dict map. The filter name refers to the dict_map_value_field_name setting. Dict supports reading/writing multiple values for the same key.
ldap: Value to be returned from an ldap search, as a variable-expression

`dict_map_value_field_name`

Default	[None]
Value	string
See Also	`dict_map_value_field`

Field in the SQL table to use for the dict_map_value_field.

`dict_map_value_field_type`

Default	`string`
Value	string
Allowed Values	`stringintuintdoublehexblobuuid`
See Also	`dict_map_value_field`

Type of the field in the SQL table for the dict_map_value_field.

`dict_name`

Default	[None]
Value	string
See Also	`dict_driver`

Name of the dict. The dict_driver setting defaults to this.

`dict_proxy_idle_timeout`

Default	[None]
Value	time (milliseconds)

How long to keep the connection open to dict server before disconnecting. 0 means immediate disconnection after finishing the operation.

`dict_proxy_name`

Default	[None]
Value	string
See Also	`dict_name`

Name of the dict to access in the dict server. This refers to the dict_name setting.

`dict_proxy_slow_warn`

Default	`5s`
Value	time (milliseconds)

Log a warning about dict lookups that take longer than this interval.

`dict_proxy_socket_path`

Default	`dict`
Value	string

Points to the dict server's UNIX socket. The path is relative to the the base_dir setting. This should be changed to dict-async if the dict driver supports asynchronous lookups (e.g. ldap, pgsql, cassandra, NOT mysql). The dict-async service allows more than one client, so this configuration prevents creating unnecessarily many dict processes.

`dict_server`

Value	Named Filter
See Also	`dict`

Named filter for the dict server settings. Add the available named dicts for the dict server under this filter using the dict settings.

For example:

dict_server {
  dict quota {
    driver = sql
    # ...
  }
  dict acl {
    driver = file
    # ...
  }
}

`dns_client_timeout`

Default	`10s`
Value	time (milliseconds)

Timeout for DNS lookups.

This is also used by the Cassandra driver for resolving cassandra_hosts. It can be changed for Cassandra only by placing it inside a cassandra filter:

cassandra {
  dns_client_timeout = 5s
}

`dotlock_use_excl`

Default	`yes`
Value	boolean

If yes, rely on O_EXCL to work when creating dotlock files.

NFS has supported O_EXCL since version 3, so yes should be safe to use by default.

`doveadm_allowed_commands`

Default	`ALL`
Value	Boolean List
Changes	Removed: 2.4.6

Lists the commands that the client may use with the doveadm server.

The setting ALL allows all commands.

WARNING

This setting provided a false sense of security and was removed. It only matched the command name, while the allowed commands themselves gave full access to any user's mails: most commands accept a -u/-A user parameter, and commands such as sync, backup and import accept parameters that access arbitrary paths. Give doveadm server access only to trusted clients.

`doveadm_api_key`

Default	[None]
Value	string
See Also	`doveadm_password`

Set an API key for use of the HTTP API for the doveadm server.

If set, this allows HTTP clients to authenticate to the doveadm HTTP server using the X-API-Key header, which contains the API key base64 encoded.

This API key must be kept secret. The doveadm API allows doing almost anything in the server, including accessing users' mailboxes.

It's possible to use both doveadm_password and API key. This allows clients to use either method to authenticate.

`doveadm_password`

Default	[None]
Value	string
See Also	`doveadm_api_key`

Specify the password, which is used by both doveadm server and client. The client sends this password to the server for authentication, and the server accepts only this password. Alternatively, doveadm HTTP API can be authenticated to using doveadm_api_key.

This password must be kept secret. The doveadm API allows doing almost anything in the server, including accessing users' mailboxes.

If doveadm server is accessed via UNIX socket that has 0600 permissions, the authentication is skipped. However, the doveadm HTTP API always requires authentication.

`doveadm_port`

Default	[None]
Value	Port Number

The destination port to be used for the next doveadm proxying hop. This implicitly enables doing a passdb lookup for finding the proxy settings.

A value of 0 means that proxying is not in use. This also means no passdb lookup is done - only userdb lookup.

`doveadm_server`

Value	Named Filter

Filter for doveadm server specific settings.

`doveadm_socket_path`

Default	`doveadm-server`
Value	string

The UNIX socket or host (host:port syntax is allowed) for connecting to the doveadm server.

`doveadm_ssl`

Default	`no`
Value	string
Allowed Values	`nosslstarttls`

TODO

`doveadm_username`

Default	`doveadm`
Value	string

The username for authentication to the doveadm service.

`doveadm_worker_count`

Default	[None]
Value	unsigned integer

If the worker count set here is non-zero, mail commands are run via this many connections to the doveadm service.

If 0, commands are run directly in the same process.

`dovecot_config_version`

Default	[None]
Value	string
Changes	Added: 2.4.0

Dovecot configuration version. It uses the same versioning as Dovecot in general, e.g. 3.0.5. This must be the first setting in the configuration file. It specifies the configuration syntax, the used setting names and the expected default values.

When there are default configuration changes in newer Dovecot versions, the existing installations will continue to work the same as before with the same default settings until this version number is increased. If there are other configuration changes, the old configuration will either keep working or there will be a clear failure at startup.

`dovecot_storage_version`

Default	[None]
Value	string
Changes	Added: 2.4.0

Dovecot storage file format version. It uses the same versioning as Dovecot in general, e.g. 3.0.5. It specifies the oldest Dovecot version that must be able to read files written by this Dovecot instance. The intention is that when upgrading Dovecot cluster, this setting is first kept as the old Dovecot version. Once the cluster is fully upgraded to a new version and there is no intention to rollback to the old version anymore, this version number can be increased.

Changed: 2.4.5 The dovecot.index.thread index, used by the IMAP THREAD command, is written in a new v2 format. The Message-ID hashes stored in it are calculated with a keyed hash using a random per-file key instead of CRC32, so users can no longer craft Message-IDs whose hashes deliberately collide. Existing v1 index files are deleted and rebuilt in the v2 format when the mailbox is next opened for threading. Older Dovecot versions don't understand the v2 format and rebuild the index in the v1 format, so keep this setting at the old version until a rollback is no longer possible.

`dsync_alt_char`

Default	`_`
Value	string

When the source and destination mailbox formats are different, it's possible for a mailbox name to exist on one source that isn't valid for the destination. Any invalid characters are replaced with the character indicated here.

`dsync_commit_msgs_interval`

Default	`100`
Value	unsigned integer

Dsync will commit this number of messages incrementally, to avoid huge transactions that fail.

`dsync_features`

Default	[None]
Value	string

This setting specifies features and workarounds that can be used with dsync. Options are specified in this setting via a space-separated list.

Available options:

empty-header-workaround: Workaround for servers (e.g. Zimbra) that sometimes send FETCH replies containing no headers.
no-header-hashes: When this setting is enabled and one dsync side doesn't support mail GUIDs (i.e. imapc), there is no fallback to using header hashes. Instead, dsync assumes that all mails with identical IMAP UIDs contain the same mail contents. This can significantly improve dsync performance with some IMAP servers that don't support caching Date/Message-ID headers.

`event_exporter`

Default	[None]
Value	Named List Filter
See Also	`event_exporter_name`

Creates a new event exporter. The filter name refers to the event_exporter_name setting.

`event_exporter_driver`

Default	`log`
Value	string
Allowed Values	`logfileunixhttp-postdrop`
See Also	Event Export: Drivers

The event exporter driver to use.

`event_exporter_file_path`

Default	[None]
Value	string

Path to event log file with event_exporter_driver = file.

`event_exporter_format`

Default	[None]
Value	string
See Also	Event Export: Formats

Format used for serializing the event.

`event_exporter_http_post_url`

Default	[None]
Value	string

Target URL for event_exporter_driver = http-post.

`event_exporter_name`

Default	[None]
Value	string
See Also	`metric_exporter`

Name of the event exporter. It is referred by the metric_exporter settings.

`event_exporter_time_format`

Default	`rfc3339`
Value	string
Allowed Values	`rfc3339unix`
See Also	Event Export: Formats

rfc3339: Serialize timestamps as strings using the RFC 3339 format (YYYY-MM-DDTHH:MM:SS.uuuuuuZ).
unix: Serialize timestamps as a floating point number of seconds since the Unix epoch.

`event_exporter_unix_connect_timeout`

Default	`250ms`
Value	time (milliseconds)
See Also	`event_exporter_unix_path`

Timeout when connecting to unix socket with event_exporter_driver = unix.

`event_exporter_unix_path`

Default	[None]
Value	string
See Also	`event_exporter_unix_connect_timeout`

Path to event unix socket with event_exporter_driver = unix.

`execute`

Default	[None]
Value	Named List Filter
See Also	Execute Scripts

Configure external execution script. Used by various different features, such as welcome. Currently only a single execute block (per feature) is allowed.

`execute_args`

Default	[None]
Value	string

External execution script arguments. The parameters are split by space characters. Currently escape characters are not supported.

`execute_driver`

Default	[None]
Value	string
Allowed Values	`unixforktcp`
See Also	Execute Scripts

How to execute the external script:

unix: Use UNIX socket connection to a script service listening in execute_unix_socket_path.
fork: Fork and execute the execute_fork_path binary directly.
tcp: Use TCP connection to a script service listening in execute_tcp_host:execute_tcp_port.

`execute_fork_path`

Default	`execute_name`
Value	string

Path to the binary that is executed with execute_driver = fork.

`execute_name`

Default	[None]
Value	string

Name of the execution script. This is the execute named filter name. It is also used to provide a default driver-specific settings:

unix: Used as the default for execute_unix_socket_path.
fork: Used as the default for execute_fork_path.
tcp: Used as the default for execute_tcp_host:execute_tcp_port.

`execute_tcp_host`

Default	`execute_name = host:`
Value	string

TCP host where to connect to with execute_driver = tcp.

`execute_tcp_port`

Default	`execute_name = :port`
Value	string

TCP port where to connect to with execute_driver = tcp.

`execute_unix_socket_path`

Default	`execute_name`
Value	string

UNIX socket path where to connect to with execute_driver = unix.

`fifo_listener`

Default	[None]
Value	Named List Filter
See Also	`service` `fifo_listener_path`

Creates a new FIFO listener for a service. The filter name refers to the fifo_listener_path setting.

`fifo_listener_group`

Default	[None]
Value	string

Group of the listener file. Empty (default) means GID 0 (root/wheel).

`fifo_listener_mode`

Default	`0600`
Value	octal unsigned integer

Mode of the file. Note that 0600 is an octal value, while 600 is a different decimal value. Setting mode to 0 disables the listener.

`fifo_listener_path`

Default	[None]
Value	String without variables
See Also	`base_dir` `fifo_listener`

Path to the FIFO, relative to base_dir setting. The fifo_listener filter name refers to this setting.

`fifo_listener_type`

Default	[None]
Value	string
Changes	Added: 2.4.0

Listener type. This string value has service-specific meaning and is used to distinguish different listener types that one service may employ.

`fifo_listener_user`

Default	[None]
Value	string

Owner of the listener file. Empty (default) means UID 0 (root).

`first_valid_gid`

Default	`1`
Value	unsigned integer
See Also	`last_valid_gid`

This setting and last_valid_gid specify the valid GID range for users.

A user whose primary GID is outside this range is not allowed to log in.

If the user belongs to any supplementary groups, the corresponding IDs are not set.

`first_valid_uid`

Default	`500`
Value	unsigned integer
See Also	`last_valid_uid`

This setting and last_valid_uid specify the valid UID range for users.

A user whose UID is outside this range is not allowed to log in.

`fs`

Default	[None]
Value	Named List Filter
See Also	Dovecot Filesystems `fs_name` `fs_driver`

Create a new fs to the list of filesystems. The filter name refers to fs_name setting.

Example:

fs posix {
  # ...
}

Since an empty fs_driver default to fs_name there is no need to specify fs_driver explicitly.

It's possible to specify the same fs multiple times by separating the fs_name and fs_driver settings:

fs compress1 {
  fs_driver = compress
}
fs compress2 {
  fs_driver = compress
}

`fs_compress_read_plain_fallback`

Default	`no`
Value	boolean
See Also	fs-compress plugin

By default fs-compress plugin fails if the file wasn't compressed. If this setting is enabled the file is returned as-is (i.e. allows reading plaintext files).

`fs_compress_write_method`

Default	[None]
Value	string
See Also	Compression Methods

Which Compression Method to use for writing new files. Empty value means that compression is disabled.

`fs_crypt_read_plain_fallback`

Default	`no`
Value	boolean

If enabled files that are not encrypted are returned as-is. By default it results in a read error.

`fs_dict_value_encoding`

Default	`raw`
Value	string
Allowed Values	`rawhexbase64`

How to encode file contents into the dict value.

`fs_driver`

Default	`fs_name`
Value	string
See Also	`fs` `fs_name`

The fs driver to use. Defaults to fs_name.

`fs_name`

Default	[None]
Value	string
See Also	`fs` `fs_driver`

Name of the fs. The fs_driver setting default to this.

`fs_posix_fsync`

Default	`yes`
Value	boolean

Configure whether fsync() is called after writes to guarantee that the file is written to disk.

`fs_posix_mode`

Default	`0600`
Value	octal unsigned integer

Mode to use for creating files.

`fs_posix_prefix`

Default	[None]
Value	string

Directory prefix where files are read from/written to.

INFO

The trailing / is not automatically added, so using e.g. /tmp/foo as prefix will cause /tmp/foofilename to be created.

`fts`

Default	[None]
Value	Named List Filter
Plugin	fts plugin

Configures the used fts driver to perform fts plugin indexing. If not specified, FTS is disabled. The filter name refers to the fts_driver setting.

Example:

fts solr {
  # ...
}

`fts_autoindex`

Default	`no`
Value	string
Allowed Values	`noyesdirect`
See Also	`fts_autoindex_max_recent_msgs` `dsync_commit_msgs_interval`
Plugin	fts plugin
Changes	Changed: 2.4.6 Changed from boolean to `no`, `yes` or `direct`.

Index mail as it is delivered or appended:

no: Don't index new mails automatically.
yes: Send a request to the indexer service to index the new mails asynchronously.
direct: Index the new mails directly in the same process after the mails have been committed. This is mainly useful when importing a lot of mails, e.g. with doveadm sync, doveadm backup or doveadm import: the mails are indexed while they are still in caches, instead of the indexer process having to read them again later from storage. The FTS index updates are kept open between the commits (see dsync_commit_msgs_interval) and written once the mailbox is closed, when an FTS search is started in the same process, or when expunges need to be processed. If direct indexing fails, the indexer service is used instead. fts_autoindex_max_recent_msgs is ignored with this value.

It can be overridden at the mailbox level, e.g. you can disable autoindexing for selected mailboxes using this setting:

Example:

fts_autoindex = yes

# ...

mailbox trash {
  special_use = Trash
  fts_autoindex = no
}

mailbox spam {
  special_use = Junk
  fts_autoindex = no
}

mailbox storage/* {
  fts_autoindex = no
}

`fts_autoindex_max_recent_msgs`

Default	[None]
Value	unsigned integer
See Also	`fts_autoindex`
Plugin	fts plugin

To exclude infrequently accessed mailboxes from automatic indexing, set this value to the maximum number of Recent flagged messages that exist in the mailbox.

A value of 0 means to ignore this setting.

Mailboxes with more flagged Recent messages than this value will not be autoindexed, even though they get deliveries or appends. This is useful for, e.g., inactive Junk folders.

Any folders excluded from automatic indexing will still be indexed, if a search on them is performed.

Example:

fts_autoindex_max_recent_msgs = 999

`fts_decoder_driver`

Default	[None]
Value	string
Allowed Values	`<empty>scripttika`
Plugin	fts plugin

Optional setting. If set, decode attachments to plaintext using the selected service and index the resulting plaintext.

`fts_decoder_script_socket_path`

Default	[None]
Value	string
Plugin	fts plugin
Changes	Changed: 2.4.0 Renamed from `fts_decoder`.

Name of the script service used to decode the attachments. We strongly recommend using fts_decoder_driver = tika instead.

Example:

fts_decoder_driver = script
fts_decoder_script_socket_path = fts-decoder

service fts-decoder {
  executable = script /path/to/fts-decoder.sh
  user = vmail
  unix_listener fts-decoder {
	mode = 0666
  }
}

`fts_decoder_tika`

Value	Named Filter
See Also	`fts_decoder_tika_url`
Plugin	fts plugin

Named filter used for Apache Tika HTTP lookups. For example:

fts_decoder_tika {
  http_client_request_timeout = 10s
}

`fts_decoder_tika_url`

Default	[None]
Value	string
See Also	`fts_decoder_tika`
Plugin	fts plugin
Changes	Added: 2.4.0 Basic authentication support (via URL) is added. Changed: 2.4.0 Renamed from `fts_tika`.

URL for Apache Tika decoder for attachments.

Example:

fts_decoder_driver = tika
fts_decoder_tika_url = http://tikahost:9998/tika/

`fts_driver`

Default	[None]
Value	string
Allowed Values	`dovecotsolrflatcurve`
Plugin	fts plugin

Configures the used fts driver to perform fts plugin indexing. The fts filter name refers to this setting.

`fts_flatcurve_substring_search`

Default	`no`
Value	boolean
Plugin	fts-flatcurve plugin

If enabled, allows substring searches (RFC 3501 compliant). However, this requires significant additional storage space. Many users today expect "Google-like" behavior, which is prefix searching, so substring searching is arguably not the modern expected behavior anyway. Therefore, even though it is not strictly RFC compliant, prefix (non-substring) searching is enabled by default.

`fts_header_excludes`

Default	[None]
Value	Boolean List
Plugin	fts plugin

The list of headers to include or exclude.

The default is the preexisting behavior, i.e. index all headers.
includes take precedence over excludes: if a header matches both, it is indexed.
The terms are case insensitive.
An asterisk * at the end of a header name matches anything starting with that header name.
The asterisk can only be used at the end of the header name. Prefix and infix usage of asterisk are not supported.

Example:

fts_header_excludes {
  Received = yes
  DKIM-* = yes
  X-* = yes
  Comments = yes
}

fts_header_includes {
  X-Spam-Status = yes
  Comments = yes
}

Received headers, all DKIM- headers and all X- experimental headers are excluded, with the following exceptions:
- Comments and X-Spam-Status are indexed anyway, as they match both excludes and includes lists.
- All other headers are indexed.

Example:

fts_header_excludes {
  * = yes
}

fts_header_includes {
  From = yes
  To = yes
  Cc = yes
  Bcc = yes
  Subject = yes
  Message-ID = yes
  In-* = yes
  X-CustomApp-* = yes
}

No headers are indexed, except those specified in the includes.

`fts_header_includes`

Default	[None]
Value	Boolean List
See Also	`fts_header_excludes`
Plugin	fts plugin

`fts_message_max_size`

Default	`unlimited`
Value	size
Plugin	fts plugin
Changes	Added: 2.4.0

Maximum body size that is processed by fts.

`fts_search_add_missing`

Default	`body-search-only`
Value	string
Allowed Values	`body-search-onlyyes`
Plugin	fts plugin

Should missing mails be added to FTS indexes before search?

With body-search-only this is done only when the search query requests searching message bodies, i.e. header searches are not updating the FTS index.

The unindexed mails are searched without FTS, i.e. either getting the headers from dovecot.index.cache or by opening the emails if the headers aren't in cache. This may be a useful optimization if the user's client only uses header searches.

INFO

Only the yes option guarantees consistent search results. Otherwise it's possible that the search results will be different depending on whether the search was performed via FTS index or not.

`fts_search_read_fallback`

Default	`yes`
Value	boolean
Plugin	fts plugin

If FTS lookup or indexing fails, fall back to searching without FTS (i.e. possibly opening all emails). This may timeout for large mailboxes and/or slow storage.

`fts_search_timeout`

Default	`30s`
Value	time
Plugin	fts plugin

When the full text search driver detects that the index isn't up-to-date, the indexer is told to index the messages and is given this much time to do so. If this time limit is reached, an error is returned, indicating that the search timed out during waiting for the indexing to complete: NO [INUSE] Timeout while waiting for indexing to finish.

A value of 0 means no timeout.

`fts_solr_batch_size`

Default	`1000`
Value	unsigned integer
Plugin	fts-solr plugin

Configures the number of mails sent to Solr in a single request.

With fts_autoindex = yes each new mail gets separately indexed on arrival, so fts_solr_batch_size only matters during the initial indexing of a mailbox.
With fts_autoindex = no new mails don't get indexed on arrival, so fts_solr_batch_size is used when indexing is triggered.

`fts_solr_soft_commit`

Default	`yes`
Value	boolean
See Also	FTS Solr: Soft Commits
Plugin	fts-solr plugin

Controls whether new mails are immediately searchable via Solr.

`fts_solr_url`

Default	[None]
Value	string
Plugin	fts-solr plugin

Required base URL for Solr.

INFO

Remember to add your core name if using solr 7+: /solr/dovecot.

Example:

fts_solr_url = http://solr.example.org:8983/solr/dovecot/
fts_solr_batch_size = 1000

`haproxy_timeout`

Default	`3secs`
Value	time

When to abort the HAProxy connection when no complete header has been received.

`haproxy_trusted_networks`

Default	[None]
Value	string

A space-separated list of trusted network ranges for HAProxy connections.

Connections from networks outside these ranges to ports that are configured for HAProxy are aborted immediately.

`hostname`

Default	`<system's real hostname@domain.tld>`
Value	string

The hostname to be used in email messages sent out by the local delivery agent (such as the Message-ID: header), in LMTP replies, and as the hostname advertised by submission SMTP service.

`http_client_connect_timeout`

Default	[None]
Value	time (milliseconds)
See Also	`http_client_request_timeout`
Changes	Added: 2.4.0

Max time to wait for TCP connect and SSL handshake to finish before retrying. 0 = use http_client_request_timeout.

`http_client_delete_request_max_attempts`

Default	[None]
Value	unsigned integer
See Also	`http_client_request_max_attempts`
Changes	Added: 2.4.0

If non-zero, override http_client_request_max_attempts for DELETE requests.

`http_client_delete_request_timeout`

Default	[None]
Value	time (milliseconds)
See Also	`http_client_request_timeout`
Changes	Added: 2.4.0

If non-zero, override http_client_request_timeout for DELETE requests.

`http_client_max_connect_attempts`

Default	[None]
Value	unsigned integer
Changes	Added: 2.4.0

Maximum number of connection attempts to a host before all associated requests fail.

If non-zero, the maximum will be enforced across all IPs for that host, meaning that IPs may be tried more than once eventually if the number of IPs is smaller than the specified maximum attempts. If the number of IPs is higher than the maximum attempts not all IPs are tried.

If 0, all IPs are tried at most once.

`http_client_max_idle_time`

Default	[None]
Value	time (milliseconds)
Changes	Added: 2.4.0

Maximum time a connection will idle. If parallel connections are idle, the duplicates will end earlier based on how many idle connections exist to that same service.

`http_client_max_parallel_connections`

Default	`1`
Value	unsigned integer
Changes	Added: 2.4.0

Maximum number of parallel connections per peer.

`http_client_max_pipelined_requests`

Default	`1`
Value	unsigned integer
Changes	Added: 2.4.0

Maximum number of pipelined requests per connection.

`http_client_proxy_password`

Default	[None]
Value	string
Changes	Added: 2.4.0

Password for HTTP proxy.

`http_client_proxy_socket_path`

Default	[None]
Value	string
See Also	`http_client_proxy_url`
Changes	Added: 2.4.0

UNIX socket path for HTTP proxy. Overrides http_client_proxy_url.

`http_client_proxy_ssl_tunnel`

Default	`yes`
Value	boolean
Changes	Added: 2.4.0

If no the HTTP proxy delegates SSL negotiation to proxy, rather than creating a CONNECT tunnel through the proxy for the SSL link.

`http_client_proxy_url`

Default	[None]
Value	string
See Also	`http_client_proxy_socket_path`
Changes	Added: 2.4.0

URL for HTTP proxy. Ignored if http_client_proxy_socket_path is set.

`http_client_proxy_username`

Default	[None]
Value	string
Changes	Added: 2.4.0

Username for HTTP proxy.

`http_client_rawlog_dir`

Default	[None]
Value	directory path
Changes	Added: 2.4.0 Changed: 2.4.6 Setting type changed. A leading `~/` in the value is now expanded to the user's home directory.

Directory for writing raw log data for debugging purposes.

WARNING

Must be writable by the process creating this log.

`http_client_read_request_max_attempts`

Default	[None]
Value	unsigned integer
See Also	`http_client_request_max_attempts`
Changes	Added: 2.4.0

If non-zero, override http_client_request_max_attempts for GET and HEAD requests.

`http_client_read_request_timeout`

Default	[None]
Value	time (milliseconds)
See Also	`http_client_request_timeout`
Changes	Added: 2.4.0

If non-zero, override http_client_request_timeout for GET and HEAD requests.

`http_client_request_absolute_timeout`

Default	[None]
Value	time (milliseconds)
Changes	Added: 2.4.0

Max total time to wait for HTTP request to finish, including all retries. 0 means no limit.

`http_client_request_max_attempts`

Default	`1`
Value	unsigned integer
Changes	Added: 2.4.0

Maximum number of attempts for a request.

`http_client_request_max_redirects`

Default	[None]
Value	unsigned integer
Changes	Added: 2.4.0

Maximum number of redirects for a request. 0 = redirects refused.

`http_client_request_timeout`

Default	`1 min`
Value	time (milliseconds)
Changes	Added: 2.4.0

Max time to wait for HTTP requests to finish before retrying.

`http_client_write_request_max_attempts`

Default	[None]
Value	unsigned integer
See Also	`http_client_request_max_attempts`
Changes	Added: 2.4.0

If non-zero, override http_client_request_max_attempts for PUT and POST requests.

`http_client_write_request_timeout`

Default	[None]
Value	time (milliseconds)
See Also	`http_client_request_timeout`
Changes	Added: 2.4.0

If non-zero, override http_client_request_timeout for PUT and POST requests.

`http_server_max_idle_time`

Default	[None]
Value	time (milliseconds)

Maximum time a connection will idle.

`http_server_max_pipelined_requests`

Default	`1`
Value	unsigned integer

Maximum number of pipelined requests per connection.

`http_server_rawlog_dir`

Default	[None]
Value	directory path
Changes	Changed: 2.4.6 Setting type changed. A leading `~/` in the value is now expanded to the user's home directory.

Directory for writing raw log data for debugging purposes.

`imap_acl_allow_anyone`

Default	`no`
Value	boolean
Plugin	imap-acl plugin

By default Dovecot doesn't allow using the IMAP anyone or authenticated identifier, because it would be an easy way to spam other users in the system.

If mail-crypt plugin is used, users who have different set of encryption keys cannot share mails, but sharing is possible within the scope of a key.

`imap_capability`

Default	[None]
Value	Boolean List

Override the IMAP CAPABILITY response.

Example of modifying capability banner by adding QUOTA and ACL, and removing IDLE:

imap_capability {
  QUOTA = yes
  ACL = yes
  IDLE = no
}

Example of setting capability banner to exactly IMAP4rev1 SASL-IR IDLE:

imap_capability = IMAP4rev1 SASL-IR IDLE

`imap_client_workarounds`

Default	[None]
Value	Boolean List

Workarounds for various IMAP client bugs can be enabled here.

The following values are currently supported:

delay-newmail: EXISTS/RECENT new-mail notifications are sent only in replies to NOOP and CHECK commands. Some clients, such as pre-2.1 versions of Mac OS X Mail, ignore them otherwise, and, worse, Outlook Express may report that the message is no longer on the server (note that the workaround does not help for OE6 if synchronization is set to Headers Only).
tb-extra-mailbox-sep: Because mailbox_list_layout = fs (mbox and dbox) confuses Thunderbird, causing extra / suffixes to mailbox names, Dovecot can be told to ignore the superfluous character instead of judging the mailbox name to be invalid.
tb-lsub-flags: Without this workaround, Thunderbird doesn't immediately recognize that LSUB replies with mailbox_list_layout = fs aren't selectable, and users may receive pop-ups with not selectable errors. Showing \Noselect flags for these replies (e.g., in mbox use) causes them to be grayed out.

`imap_fetch_failure`

Default	`disconnect-immediately`
Value	string
Allowed Values	`disconnect-afterdisconnect-immediatelyno-after`

Behavior when IMAP FETCH fails due to some internal error. Options:

disconnect-immediately

The FETCH is aborted immediately and the IMAP client is disconnected.

disconnect-after

The FETCH runs for all the requested mails returning as much data as possible. The client is finally disconnected without a tagged reply.

no-after

Same as disconnect-after, but tagged NO reply is sent instead of disconnecting the client.

If the client attempts to FETCH the same failed mail more than once, the client is disconnected.

This is to avoid clients from going into infinite loops trying to FETCH a broken mail.

`imap_filter_sieve_max_redirects`

Default	`1024`
Value	unsigned integer
See Also	`sieve_max_redirects` `sieve_max_actions`
Plugin	imap-filter-sieve plugin
Changes	Added: 2.4.6 Setting to limit the cumulative number of redirects performed by a single IMAP `FILTER=SIEVE` command is added.

The maximum cumulative number of messages that may be redirected across a single IMAP FILTER=SIEVE command.

0 disables redirecting via FILTER=SIEVE entirely: such a command is aborted rather than performing any redirect. Set this to the maximum value to allow an unlimited number of redirects.

Unlike sieve_max_redirects, which limits redirect actions per single script execution (that is, per message), this setting bounds the total number of messages redirected while a script is run against a whole set of messages via the IMAP FILTER command. It throttles bulk forwarding ("redirect bombs") when a redirect script is applied to a large mailbox.

When the limit is reached, the FILTER command aborts with an error.

`imap_hibernate_nonidle_timeout`

Default	[None]
Value	time
See Also	`imap_hibernate_timeout` Hibernating Connections Without IDLE
Changes	Added: 2.4.6

How long to wait after the client's last command has finished before moving the connection to the imap-hibernate process, even though the client is not in IDLE state. 0 disables this.

Any input from the client moves the connection back to a new imap process. Set this above the polling interval of the clients in use, because each wake-up recreates an imap process.

If messages are expunged while the connection is hibernated, the client is asked to relogin.

`imap_hibernate_timeout`

Default	[None]
Value	time
See Also	`imap_hibernate_nonidle_timeout` IMAP Hibernation

How long to wait while the client is in IDLE state before moving the connection to the hibernate process, to save on memory use, and close the existing IMAP process.

If nothing happens for this long while client is IDLEing, move the connection to imap-hibernate process and close the old imap process. This saves memory, because connections use very little memory in imap-hibernate process. The downside is that recreating the imap process back uses some additional system resources.

`imap_id_retain`

Default	`no`
Value	boolean

When proxying IMAP connections to other hosts, this variable must be enabled to forward the IMAP ID command provided by the client.

This setting enables the %{client_id} variable for auth processes. See Authentication variables.

`imap_id_send`

Default	`name=%{dovecot:name}`
Value	String List

Which ID field names and values to send to clients.

You can access the default values by using Distribution Variables.

imap_id_send {
  name = %{dovecot:name}
  version = %{dovecot:version}
  support-url = http://example.com/
}

`imap_literal_minus`

Default	`no`
Value	boolean

Enable IMAP LITERAL- (RFC 7888) extension (replaces LITERAL+)?

`imap_logout_format`

Default	`in=%{input} out=%{output} deleted=%{deleted} expunged=%{expunged} trashed=%{trashed} hdr_count=%{fetch_hdr_count} hdr_bytes=%{fetch_hdr_bytes} body_count=%{fetch_body_count} body_bytes=%{fetch_body_bytes}`
Value	String without variables

This setting specifies the IMAP logout format string. Supported variables, in addition to Mail user variables are:

Variable Name	Description
`%{input}`	Total number of bytes read from client
`%{output}`	Total number of bytes sent to client
`%{fetch_hdr_count}`	Number of mails with mail header data sent to client
`%{fetch_hdr_bytes}`	Number of bytes with mail header data sent to client
`%{fetch_body_count}`	Number of mails with mail body data sent to client
`%{fetch_body_bytes}`	Number of bytes with mail body data sent to client
`%{deleted}`	Number of mails where client added Deleted flag
`%{expunged}`	Number of mails that client expunged, which does not include automatically expunged mails
`%{autoexpunged}`	Number of mails that were automatically expunged after client disconnected
`%{trashed}`	Number of mails that client copied/moved to the special_use=Trash mailbox.
`%{appended}`	Number of mails saved during the session

`imap_metadata`

Default	`no`
Value	boolean

Dovecot supports the IMAP METADATA extension (RFC 5464), which allows per-mailbox, per-user data to be stored and accessed via IMAP commands. Set this parameter's value to yes if you wish to activate the IMAP METADATA commands.

Note: If activated, a dictionary needs to be configured, via the mail_attribute setting.

Example:

# Store METADATA information within user's Maildir directory
mail_attribute {
  dict file {
    path = %{home}/Maildir/dovecot-attributes
  }
}

protocol imap {
  imap_metadata = yes
}

`imap_urlauth_host`

Default	[None]
Value	URL

Specifies the host used for URLAUTH URLs. Only this host is accepted in the client-provided URLs. Using * value (not recommended) allows all hosts and the generated URLs use hostname as the host.

An empty value disables the URLAUTH extension entirely.

WARNING

URLAUTH in current versions of Dovecot is broken in several ways. This will be fixed in the future, but activating URLAUTH support on production systems is not recommended.

INFO

This setting is REQUIRED for the URLAUTH (RFC 4467) extension to be active.

`imap_urlauth_logout_format`

Default	`in=%{input} out=%{output}`
Value	String without variables
See Also	`imap_urlauth_host`

Specifies the logout format used with the URLAUTH extension in IMAP operation.

WARNING

This setting is currently not used.

Variables allowed:

Name	Description
`%{input}`	Total number of bytes read from the client
`%{output}`	Total number of bytes sent to the client

`imap_urlauth_port`

Default	`143`
Value	Port Number
See Also	`imap_urlauth_host`

The port is used with the URLAUTH extension in IMAP operation.

`imapc_cmd_timeout`

Default	`5 mins`
Value	time

How long to wait for a reply to an IMAP command sent to the remote IMAP server before disconnecting and retrying.

`imapc_connection_retry_count`

Default	`1`
Value	unsigned integer

How many times to retry connection against a remote IMAP server?

`imapc_connection_retry_interval`

Default	`1 secs`
Value	time (milliseconds)

How long to wait between retries against a remote IMAP server?

`imapc_connection_timeout_interval`

Default	`30secs`
Value	time (milliseconds)

How long to wait before considering a connection attempt as timed out.

`imapc_features`

Default	[None]
Value	Boolean List
Changes	Changed: 2.4.0 Several features are now automatically enabled and the respective flags dropped. In their place new flags to disable these features were added.

List of features, optimizations, and workarounds that can be enabled.

Changed: 2.4.3 Any remote IMAP server extension can now be disabled by using no- prefixed with the capability name. For example no-sort, no-sort=display or no-quota.

Features

no-acl

If the imap-acl plugin is loaded, the imapc acl feature is automatically enabled. With it IMAP ACL commands (MYRIGHTS, GETACL, SETACL, DELETEACL) are proxied to the imapc remote location. Note that currently these commands are attempted to be used even if the remote IMAP server doesn't advertise the ACL capability.

To disable this feature either unload the imap-acl plugin or provide this feature.

Changed: 2.4.0

Earlier versions had an "acl" feature, which is now enabled by default.

no-delay-login: Immediately connect to the remote server. By default this is delayed until a command requires a connection.

Changed: 2.4.0

Earlier versions had a "delay-login" feature, which is now enabled by default.

gmail-migration: Enable GMail-specific migration. Use IMAP X-GM-MSGID as POP3 UIDL. Add $GMailHaveLabels keyword to mails that have X-GM-LABELS except for Muted keyword (to be used for migrating only archived emails in All Mails). Add pop3_deleted_flag to mails that don't exist in POP3 server.

no-modseq: Disable access to MODSEQ and HIGHESTMODSEQ fields. By default these fields are available if the remote server advertises the CONDSTORE or the QRESYNC capability. If modseqs are disabled, or not supported by the new server, they can still be used if imapc is configured to have local index files.

Changed: 2.4.0

Earlier versions had a "modseq" feature, which is now enabled by default.

proxyauth: Use Sun/Oracle IMAP-server specific PROXYAUTH command to do master user authentication. Normally this would be done using the SASL PLAIN authentication.

send-id: Send session ID with the IMAP ID x-session-ext-id parameter. If login_trusted_networks on the target host is configured to trust the connecting imapc IP, the session ID is preserved as the new imapc connection's session ID prefix.

throttle:<INIT>:<MAX>:<SHRINK>

When receiving [THROTTLED] response (from GMail), throttling is applied.

INIT = initial throttling msecs (default: 50 ms), afterwards each subsequent [THROTTLED] doubles the throttling until MAX is reached (default: 16000 ms). When [THROTTLED] is not received for a while, it's shrunk again. The initial shrinking is done after SHRINK (default: 500 ms). If [THROTTLED] is received again within this timeout, it's doubled, otherwise both throttling and the next shrinking timeout is shrank to 3/4 the previous value.

Optimizations

no-fetch-bodystructure: Disable fetching of IMAP BODY and BODYSTRUCTURE from the remote server. Instead, the whole message body is fetched to regenerate them.

Changed: 2.4.0

Earlier versions had a "fetch-bodystructure" feature, which is now enabled by default.

no-fetch-headers: Disable fetching of specific message headers from the remote server using the IMAP FETCH BODY.PEEK[HEADER.FIELDS(...)] command. Instead, the whole header is fetched and the wanted headers are parsed from it.

Changed: 2.4.0

Earlier versions had a "fetch-headers" feature, which is now enabled by default.

no-fetch-size: Disable fetching of message sizes from the remote server using the IMAP FETCH RFC822.SIZE command. Instead, the whole message body is fetched to calculate the size.

Changed: 2.4.0

Earlier versions had a "rfc822.size" feature, which is now enabled by default.

no-metadata: Disable the detection of the METADATA capability from the remote server. The client will receive a NO [UNAVAILABLE] response for any request that requires access to metadata on the remote server (the same happens if the server does not announce the capability at all).

no-search: Disable searching messages using the IMAP SEARCH command. Instead, all the message headers/bodies are fetched to perform the search locally.

Changed: 2.4.0

Earlier versions had a "search" feature, which is now enabled by default.

Workarounds

fetch-fix-broken-mails: If a FETCH returns NO (but not NO [LIMIT] or NO [SERVERBUG]), assume the mail is broken in server and just treat it as if it were an empty email.

DANGER

This is often a dangerous option! It's not safe to assume that NO means a permanent error rather than a temporary error. This feature should be enabled only for specific users who have been determined to be broken.

fetch-msn-workarounds: Try to ignore wrong message sequence numbers in FETCH replies whenever possible, preferring to use the returned UID number instead.

no-examine: Use SELECT instead of EXAMINE even when we don't want to modify anything in the mailbox. This is a Courier-workaround where it didn't permanently assign UIDVALIDITY to an EXAMINEd mailbox, but assigned it for SELECTed mailbox.

no-qresync Added: 2.4.0: This can be used to work around a Zimbra bug where it doesn't send untagged "OK [CLOSED]" imap-resp-code when selecting a folder.

zimbra-workarounds: Fetch full message using BODY.PEEK[HEADER] BODY.PEEK[TEXT] instead of just BODY.PEEK[] because the header differs between these two when there are illegal control chars or 8bit chars. This mainly caused problems with dsync, but this should no longer be a problem and there's probably no need to enable this workaround.

`imapc_host`

Default	[None]
Value	string

The remote IMAP host to connect to.

`imapc_list_prefix`

Default	[None]
Value	string

Access only mailboxes under this prefix.

Example, for a source IMAP server that uses an INBOX namespace prefix:

imapc_list_prefix = INBOX

`imapc_master_user`

Default	[None]
Value	string
See Also	`imapc_password` `imapc_user`

The master username to authenticate as on the remote IMAP host.

To authenticate as a master user but use a separate login user, the following configuration should be employed, where the credentials are represented by masteruser and masteruser-secret:

imapc_user = %{user}
imapc_master_user = masteruser
imapc_password = masteruser-secret

Mail user variables can be used.

`imapc_max_idle_time`

Default	`29 mins`
Value	time

Send a command to the source IMAP server as a keepalive after no other command has been sent for this amount of time.

Dovecot will send either NOOP or DONE to the source IMAP server.

`imapc_max_line_length`

Default	`unlimited`
Value	size

The maximum line length to accept from the remote IMAP server.

This setting is used to limit maximum memory usage.

`imapc_password`

Default	[None]
Value	string
See Also	`imapc_master_user` `imapc_user` `imapc_sasl_mechanisms`

The authentication password for the remote IMAP server.

If using master users, this setting will be the password of the master user.

`imapc_port`

Default	`143`
Value	Port Number

The port on the remote IMAP host to connect to.

`imapc_rawlog_dir`

Default	[None]
Value	directory path
See Also	rawlog
Changes	Changed: 2.4.6 Setting type changed.

Log all IMAP traffic input/output to this directory.

`imapc_sasl_mechanisms`

Default	`plain`
Value	Boolean List

The SASL mechanisms to use for authentication when connection to a remote IMAP server.

The first one advertised by the remote IMAP sever is used.

imapc_sasl_mechanisms {
  external = yes
  plain = yes
  login = yes
}

Supported mechanisms are:

ANONYMOUS
EXTERNAL
LOGIN
OAUTHBEARER
PLAIN
SCRAM-SHA-1
SCRAM-SHA-1-PLUS
SCRAM-SHA-256
SCRAM-SHA-256-PLUS
XOAUTH2

Note that imapc_password is ignored for ANONYMOUS and EXTERNAL mechanisms. For OAUTHBEARER and XOAUTH2 imapc_password should be bearer token.

`imapc_ssl`

Default	`no`
Value	string
Allowed Values	`noimapsstarttls`

Use TLS to connect to the remote IMAP server.

Value	Description
`no`	No TLS
`imaps`	Explicitly connect to remote IMAP port using TLS
`starttls`	Use IMAP STARTTLS command to switch to TLS connection

`imapc_ssl_verify`

Default	`yes`
Value	boolean
See Also	`imapc_ssl`
Changes	Removed: 2.4.0 Dropped in favor of using the global `ssl_client_require_valid_cert`.

Verify remote IMAP TLS certificate?

Verification may be disabled during testing, but should be enabled during production use.

Only used if imapc_ssl is enabled.

`imapc_user`

Default	`%{owner_user}`
Value	string
See Also	`imapc_master_user` `imapc_password` `imapc_sasl_mechanisms`

The user identity to be used for performing a regular IMAP LOGIN to the source IMAP server.

Mail user variables can be used.

`imapsieve_expunge_discarded`

Default	`no`
Value	boolean
See Also	sieve-imapsieve plugin
Plugin	imap-sieve plugin

This setting determines whether de IMAPSieve plugin implicitly also expunges messages that were discarded by the executed Sieve script sequence; i.e., Sieve yielded no (implicit) keep.

`imapsieve_from`

Default	[None]
Value	Named List Filter
See Also	sieve-imapsieve plugin
Plugin	imap-sieve plugin

Only execute the administrator Sieve scripts for the mailbox configured with sieve_script and type before or after when the message originates from the indicated mailbox. The filter name refers to the imapsieve_from_name setting. Therefore, the contained sieve_script blocks only apply when the source mailbox of the IMAP action match this filter.

`imapsieve_from_name`

Default	[None]
Value	string
See Also	sieve-imapsieve plugin
Plugin	imap-sieve plugin

The name of the source mailbox for IMAPSieve before or after scripts. The imapsieve_from filter refers to this setting.

`imapsieve_url`

Default	[None]
Value	URL
See Also	sieve-imapsieve plugin
Plugin	imap-sieve plugin

If set, support for user Sieve scripts in IMAP is enabled.

The value is an URL pointing to the ManageSieve server that users must use to upload their Sieve scripts.

Leave this setting empty if you don't want users to have the ability to associate Sieve scripts with mailboxes.

This has no effect on the administrator-controlled Sieve scripts.

imapsieve_url = sieve://sieve.example.com

`import_environment`

Default	`TZ=%{env:TZ} CORE_OUTOFMEM=%{env:CORE_OUTOFMEM} CORE_ERROR=%{env:CORE_ERROR} PATH=%{env:PATH} MALLOC_MMAP_THRESHOLD_=131072 Also systemd environments: LISTEN_PID=%{env:LISTEN_PID} LISTEN_FDS=%{env:LISTEN_FDS} NOTIFY_SOCKET=%{env:NOTIFY_SOCKET}`
Value	String List

A list of environment key=value pairs, that are preserved and passed to all child processes.

The value can be determined from the existing environment upon Dovecot startup or directly specified.

Example:

import_environment {
  TZ = :/etc/localtime
  TMPDIR = /dovecot-tmp
}

`inet_listener`

Default	[None]
Value	Named List Filter
See Also	`service` `inet_listener_name`

Creates a new network socket listener for a service. The filter name refers to the inet_listener_name setting.

`inet_listener_haproxy`

Default	`no`
Value	boolean

If yes, this listener is configured for use with HAProxy. It expects a Proxy Protocol header right after accepting the connection. Connections are aborted immediately if this protocol is violated.

`inet_listener_listen`

Default	`* ::`
Value	Boolean List
Changes	Changed: 2.4.6 Renamed from `listen`, which still works as an alias.

List of IP addresses or hostnames on which external network connections will be handled.

* listens at all IPv4 interfaces, and :: listens at all IPv6 interfaces.

Example:

listen = 127.0.0.1 192.168.0.1

The setting can be used globally, inside a service { .. } and inside an inet_listener, where the most specific value wins, e.g.:

service imap-login {
  inet_listener imap {
    listen = 192.168.0.1
  }
}

`inet_listener_name`

Default	[None]
Value	string
See Also	`inet_listener_type` `inet_listener`

Name of this listener. It is meant to be descriptive for humans (e.g. imap, imaps), but it is also used by services to determine the socket type, unless inet_listener_type overrides it. The inet_listener filter name refers to this setting.

`inet_listener_port`

Default	[None]
Value	Port Number
See Also	`inet_listener_listen`

Port number where to listen. 0 disables the listener.

`inet_listener_ssl`

Default	`no`
Value	boolean
See Also	`ssl`

If yes, the listener does an immediate SSL/TLS handshake after accepting a connection. This is needed for e.g. the imaps and pop3s ports.

INFO

All listeners with ssl=yes will be removed if the global ssl setting is no.

Regardless of the value for listener's ssl setting, some services will still try to initialize encryption if the global ssl is yes. This is for example done to accommodate STARTTLS commands for IMAP/SUBMISSION/LMTP protocols. In other words, SSL is truly disabled only when the global ssl is no.

Note: Do not confuse this with the ssl setting. When used as inet_listener { ssl }, it expands to this inet_listener_ssl setting.

`inet_listener_type`

Default	[None]
Value	string
Changes	Added: 2.4.0

Listener type. This string value has service-specific meaning and is used to distinguish different listener types that one service may employ.

`info_log_path`

Default	`log_path`
Value	string

The log file to use for informational messages.

`instance_name`

Default	`dovecot`
Value	string

For multi-instance setups, supply the unique name of this Dovecot instance.

This simplifies use of commands such as doveadm: rather than using -c and the config path, you can use the -i flag with the relevant instance name.

`language`

Default	`<textcat dir>`
Value	Named List Filter
Dependencies	`language_default`
See Also	`textcat_config_path` FTS Tokenization
Plugin	fts plugin

Defines a language to be used in tokenization.

At least one language must be specified and one single language must be flagged as the default language using language_default = yes.

The language listed first is the default and is used when language recognition fails.

The filters used for stemming and stopwords are language dependent.

Language detection uses only the textcat fingerprints of the listed languages; see textcat_filter_languages.

Example:

language en {
  default = yes
}
language de {
}

`language_default`

Default	`no`
Value	boolean
Dependencies	`language`
See Also	FTS Tokenization
Plugin	fts plugin

The language marked as default will be used when language detection cannot identify the proper language of the text being processed.

Exactly one language must be marked with this flag.

`language_filter_normalizer_icu_id`

Default	`Any-Lower; NFKD; [: Nonspacing Mark :] Remove; NFC; [\x20] Remove`
Value	string
See Also	Filter Configuration
Plugin	fts plugin
Changes	Changed: 2.4.6 The default ID and its variants without `NFC` and/or `[\x20] Remove` are implemented internally without libicu. Other IDs require the `lang_filter_normalizer_icu` module.

Description of the normalizing/transliterating rules to use.

See Normalizer Format for syntax.

These IDs are implemented internally by Dovecot:

Any-Lower; NFKD; [: Nonspacing Mark :] Remove; NFC; [\x20] Remove
Any-Lower; NFKD; [: Nonspacing Mark :] Remove; [\x20] Remove
Any-Lower; NFKD; [: Nonspacing Mark :] Remove; NFC
Any-Lower; NFKD; [: Nonspacing Mark :] Remove

The ID must match exactly, including the spaces. Any other ID requires the lang_filter_normalizer_icu module, which uses libicu. See Filter Configuration.

`language_filter_stopwords_dir`

Default	[None]
Value	string
See Also	FTS Tokenization
Plugin	fts plugin

Path to the directory containing stopword files. The files inside the directory have names with the form /stopwords_<lang>.txt.

See Languages for the list of stopword files that are currently distributed with Dovecot.

More languages can be obtained from:

`language_filters`

Default	[None]
Value	Boolean List
See Also	FTS Tokenization Filter Configuration
Plugin	fts plugin

The list of filters to apply.

See Filter Configuration for configuration information.

`language_tokenizer_address_token_maxlen`

Default	`250`
Value	unsigned integer
See Also	FTS Tokenization
Plugin	fts plugin

Maximum length of token, before an arbitrary cut off is made.

`language_tokenizer_generic_algorithm`

Default	`simple`
Value	string
Allowed Values	`simpletr29`
See Also	FTS Tokenization
Plugin	fts plugin

Defines the method for finding word boundaries.

Value	Description
`simple`	Faster algorithm that works for many texts, especially using the latin alphabets, but leaves corner cases.
`tr29`	Implements a version of Unicode technical report 29 word boundary lookup. It might work better with texts containing e.g. Katakana or Hebrew characters, but it is not possible to use a single algorithm for all existing languages.

`language_tokenizer_generic_token_maxlen`

Default	`30`
Value	unsigned integer
See Also	FTS Tokenization
Plugin	fts plugin

Maximum length of token, before an arbitrary cut off is made.

`language_tokenizer_generic_wb5a`

Default	`no`
Value	boolean
See Also	FTS Tokenization
Plugin	fts plugin

Unicode TR29 rule WB5a setting to the tr29 tokenizer. Splits prefixing contracted words from base word. E.g. l'homme -> l and homme. Together with a language specific stopword list unnecessary contractions can thus be filtered away. This is disabled by default and only works with the TR29 algorithm.

Enable by declaring:

`language_tokenizer_kuromoji_icu_id`

Default	`Any-NFKC`
Value	string
See Also	FTS Tokenization
Plugin	fts plugin

Description of the normalizing/transliterating rules to use. See Normalizer Format for syntax.

Defaults to Any-NFKC which is quite good for CJK text mixed with latin alphabet languages. It transforms CJK characters to full-width encoding and transforms latin ones to half-width. The NFKC transformation is described above.

WARNING

If this setting is changed, existing FTS indexes will produce unexpected results. The FTS indexes should be recreated in this case.

`language_tokenizer_kuromoji_token_maxlen`

Default	`1024`
Value	unsigned integer
See Also	FTS Tokenization
Plugin	fts plugin

Maximum length of token, before an arbitrary cut off is made.

`language_tokenizers`

Default	`generic email-address`
Value	Boolean List
See Also	FTS Tokenization Tokenizer Configuration
Plugin	fts plugin

The list of tokenizers to use.

See Tokenizer Configuration for configuration information.

`last_login`

Value	Named Filter
Plugin	last-login plugin

Named filter for initializing dictionary used to store last login information.

Example:

redis_host = 127.0.0.1
redis_port = 6379
last_login {
  dict redis {
  }
}

`last_login_dict_fields`

Default	[None]
Value	String List
Plugin	last-login plugin
Changes	Added: 2.4.5

List of additional key/value pairs to be updated in the dictionary. Both keys and values support variable expansion.

`last_login_key`

Default	`last-login/%{user}`
Value	string
Plugin	last-login plugin

The key that is updated in the dictionary with the last login timestamp.

`last_login_precision`

Default	`s`
Value	string
Allowed Values	`smsusns`
Plugin	last-login plugin

Precision for last login timestamp.

`last_valid_gid`

Default	`unlimited`
Value	unsigned integer
See Also	`first_valid_gid`

This setting and first_valid_gid specify the valid GID range for users.

A user whose primary GID is outside this range is not allowed to log in.

If the user belongs to any supplementary groups, the corresponding IDs are not set.

`last_valid_uid`

Default	`unlimited`
Value	unsigned integer
See Also	`first_valid_uid`

This setting and first_valid_uid specify the valid UID range for users.

A user whose UID is outside this range is not allowed to log in.

`lazy_expunge_mailbox`

Default	[None]
Value	string
See Also	lazy-expunge storage locations
Plugin	lazy-expunge plugin

The mailbox to move messages to when expunged. This setting MUST be defined or else lazy-expunge plugin will not be active.

lazy_expunge_mailbox = .EXPUNGED
namespace inbox {
  mailbox Drafts {
    lazy_expunge_mailbox =
  }
  namespace "External accounts" {
    lazy_expunge_mailbox =
  }
}

`lazy_expunge_only_last_instance`

Default	`yes`
Value	boolean
Plugin	lazy-expunge plugin
Changes	Changed: 2.4.3 Changed from `no` to `yes`.

If yes, only move to expunged storage if this is the last copy of the message in the user's account. This prevents the same mail from being duplicated in the lazy-expunge folder as the mail becomes expunged from all the folders it existed in.

This setting prevents copying mail to the lazy-expunge folder when using the IMAP MOVE command. When using COPY/EXPUNGE, this setting prevents duplicates only with the following mailbox formats:

Maildir (with maildir_copy_with_hardlinks = yes, which is the default)
sdbox/mdbox

`lda_mailbox_autocreate`

Default	`no`
Value	boolean

Should LDA create a nonexistent mailbox automatically when attempting to save a mail message?

`lda_mailbox_autosubscribe`

Default	`no`
Value	boolean

Should automatically created mailboxes be subscribed to?

`lda_original_recipient_header`

Default	`<lda/lmtp specific>`
Value	string

The header from which the original recipient address (used in the SMTP RCPT TO: address) is obtained if that address is not available elsewhere.

With LDA the default is based on the username in -d parameter. With LMTP Server the default is the same as RCPT TO.

Example:

lda_original_recipient_header = X-Original-To

`ldap_auth_dn`

Default	[None]
Value	string

Specify the Distinguished Name (the username used to login to the LDAP server).

Leave it commented out to bind anonymously (useful with passdb_ldap_bind = yes).

Example: ldap_auth_dn = uid=dov-read,dc=example,dc=com,dc=.

`ldap_auth_dn_password`

Default	[None]
Value	string

Password for LDAP server. Used if ldap_auth_dn is specified.

`ldap_auth_sasl_authz_id`

Default	[None]
Value	string

SASL authorization ID, ie. the ldap_auth_dn_password is for this "master user", but the ldap_auth_dn is still the logged in user. Normally you want to keep this empty.

`ldap_auth_sasl_mechanisms`

Default	[None]
Value	Boolean List

List of SASL mechanism names to use.

`ldap_auth_sasl_realm`

Default	[None]
Value	string

SASL realm to use.

`ldap_base`

Default	[None]
Value	string

LDAP base.

Settings variables can be used. Changed: 2.4.3 To avoid unwanted escaping of the output, add | safe filter to the variable.

Added: 2.4.6 With the LDAP storage driver storage the variables are escaped. That storage also supports %{name}, which expands to the name of the Sieve script.

Examples:

ldap_base = dc=mail, dc=example, dc=org
ldap_base = %{passdb:classOfServiceDN | safe}

`ldap_connection_group`

Default	[None]
Value	string

Only databases with the same connection group share the ldap connections. By default all the databases have the same ""(empty string) default connection group, and as such share the connections.

`ldap_debug_level`

Default	[None]
Value	unsigned integer

LDAP library debug level as specified by LDAP_DEBUG_* in ldap_log.h.

Value -1 means everything.

You may need to recompile OpenLDAP with debugging enabled to get enough output.

`ldap_deref`

Default	`never`
Value	string
Allowed Values	`neversearchingfindingalways`

Specify dereference which is set as an LDAP option.

`ldap_max_idle_time`

Default	[None]
Value	time

Disconnect from LDAP server after connection has been idle for this many seconds.

`ldap_scope`

Default	`subtree`
Value	string
Allowed Values	`baseonelevelsubtree`

This specifies the search scope.

`ldap_starttls`

Default	`no`
Value	boolean

Set to yes to use TLS to connect to the LDAP server.

`ldap_uris`

Default	[None]
Value	string

LDAP URIs to use.

Configure this setting to specify what LDAP server(s) to connect to.

The URIs are in syntax protocol://host:port.

Example: ldap_uris = ldaps://secure.domain.org

`ldap_version`

Default	`3`
Value	unsigned integer

LDAP protocol version to use. Likely 2 or 3.

`listen`

Default	[None]
Value	Boolean List
See Also	`inet_listener_listen`

Alias for inet_listener_listen.

`lmtp_add_received_header`

Default	`yes`
Value	boolean

Controls if "Received:" header should be added to delivered mails.

`lmtp_client_workarounds`

Default	[None]
Value	Boolean List

Configures the list of active workarounds for LMTP client bugs. Supported workaround identifiers are:

whitespace-before-path: Allow one or more spaces or tabs between 'MAIL FROM:' and path and between 'RCPT TO:' and path.
mailbox-for-path: Allow using bare Mailbox syntax (i.e., without <...>) instead of full path syntax.

`lmtp_hdr_delivery_address`

Default	`final`
Value	string
Allowed Values	`alternativefinalnone`

The recipient address to use for the "Delivered-To:" header and the relevant "Received:" header.

Options:

alternative: Address from the RCPT TO OCRPT parameter
final: Address from the RCPT TO command
none: No address (always used for messages with multiple recipients)

`lmtp_proxy`

Default	`no`
Value	boolean
See Also	proxy passdb

If yes, LMTP sessions perform a passdb lookup to see if the user should be proxied. The user is proxied only if the proxy extra field is returned. The proxy destination is determined via returned passdb extra fields.

`lmtp_proxy_rawlog_dir`

Default	[None]
Value	string
See Also	rawlog

Directory location to store raw LMTP proxy protocol traffic logs.

Mail service user variables can be used. However, because LMTP session starts without a user, all user-specific variables expand to empty.

`lmtp_rawlog_dir`

Default	[None]
Value	string
See Also	rawlog

Directory location to store raw LMTP protocol traffic logs.

Mail service user variables can be used. However, because LMTP session starts without a user, all user-specific variables expand to empty.

`lmtp_rcpt_check_quota`

Default	`no`
Value	boolean

Should quota be verified before a reply to RCPT TO is issued?

If active, this creates a small amount of extra overhead so it is disabled by default.

`lmtp_save_to_detail_mailbox`

Default	`no`
Value	boolean

If the recipient address includes a detail element / role (as in user+detail format), save the message to the detail mailbox.

`lmtp_user_concurrency_limit`

Default	`10`
Value	unsigned integer
Changes	Changed: 2.4.1 Changed from `unlimited` to `10`.

Limit the number of concurrent deliveries to a single user to this maximum value.

It is useful if one user is receiving numerous mail messages and thereby causing delays to other deliveries.

To prevent limiting concurrent user deliveries set this to unlimited.

`lock_method`

Default	`fcntl`
Value	string
Allowed Values	`fcntlflockdotlock`

Specify the locking method to use for index files.

Options:

dotlock: mailboxname.lock file created by almost all software when writing to mboxes. This grants the writer an exclusive lock over the mbox, so it's usually not used while reading the mbox so that other processes can also read it at the same time. So while using a dotlock typically prevents actual mailbox corruption, it doesn't protect against read errors if mailbox is modified while a process is reading.
flock: flock() system call is quite commonly used for both read and write locking. The read lock allows multiple processes to obtain a read lock for the mbox, so it works well for reading as well. The one downside to it is that it doesn't work if mailboxes are stored in NFS.
fcntl: Very similar to flock, also commonly used by software. In some systems this fcntl() system call is compatible with flock(), but in other systems it's not, so you shouldn't rely on it. fcntl works with NFS if you're using lockd daemon in both NFS server and client.

`log_core_filter`

Default	[None]
Value	string

Crash after logging a matching event. The syntax of the filter is described in Global Metric Filters.

For example:

log_core_filter = category=error

will crash any time an error is logged, which can be useful for debugging.

WARNING

Using source_location in the filter disables caching the filter results, which makes every debug log call several times slower. Use it only temporarily while debugging. See Performance With source_location.

`log_debug`

Default	[None]
Value	string

Filter to specify what debug logging to enable. The syntax of the filter is described in Global Metric Filters.

WARNING

INFO

This will eventually replace mail_debug and auth_debug settings.

`log_path`

Default	`syslog`
Value	string
See Also	`debug_log_path` `info_log_path`

Specify the log file to use for error messages.

Options:

syslog: Log to syslog
/dev/stderr: Log to stderr

If you don't want to use syslog, or if you just can't find the Dovecot's error logs, you can make Dovecot log elsewhere as well:

log_path = /var/log/dovecot.log

If you don't want errors, info, and debug logs all in one file, specify info_log_path or debug_log_path as well:

log_path = /var/log/dovecot.log
info_log_path = /var/log/dovecot-info.log

`log_timestamp`

Default	`%b %d %H:%M:%S`
Value	String without variables

The prefix for each line written to the log file.

% variables are in strftime(3) format.

`login_log_format`

Default	`%{message}: %{elements}`
Value	String without variables

The formatting of login log messages.

Variables allowed (in addition to Global variables):

Variable Name	Description
`%{elements}`	A `login_log_format_elements` string
`%{message}`	The log data

`login_log_format_elements`

Default	`user=<%{user}> method=%{mechanism} rip=%{remote_ip} lip=%{local_ip} mpid=%{mail_pid} %{secured} session=<%{session}>`
Value	String without variables

A space-separated list of elements of the login log formatting.

Elements that have a non-empty value are joined together to form a comma-separated string.

Example:

doveconf

# If `secured` is empty, the output for `%{elements}` will look like:
# `user=<user>, method=PLAIN, session=<abc>`
login_log_format_elements = user=<%{user}> method=%{mechanism} %{secured} session=<%{session}>

Login variables can be used.

`login_plugin_dir`

Default	`/usr/lib64/dovecot/login`
Value	string

Location of the login plugin directory.

`login_plugins`

Default	[None]
Value	Boolean List

List of plugins to load for IMAP and POP3 login processes.

`login_proxy_max_disconnect_delay`

Default	[None]
Value	time

Specify the delayed disconnection interval of clients when there is a server mass-disconnect.

For prevention of load spikes when a backend server fails or is restarted, disconnection is spread over the amount of time indicated.

0 disables the delay.

`login_proxy_max_reconnects`

Default	`3`
Value	unsigned integer

How many times login proxy will attempt to reconnect to destination server on connection failures (3 reconnects = total 4 connection attempts).

Reconnecting is done for most types of failures, except for regular authentication failures.

There is a 1 second delay between each reconnection attempt.

If login_proxy_timeout is reached, further reconnects aren't attempted.

`login_proxy_rawlog_dir`

Default	[None]
Value	string
See Also	rawlog

Login processes write rawlogs for proxied connections to this directory for debugging purposes. Note that login processes are usually chrooted, so the directory is relative to $base_dir/login/.

Changed: 2.4.2 You can use Login Variables with this setting.

`login_proxy_timeout`

Default	`30 secs`
Value	time (milliseconds)

Timeout for login proxy failures.

The timeout covers everything from the time connection is started until a successful login reply is received.

This can be overwritten by proxy passdb passdb extra field.

This setting applies only to proxying via login processes, not to lmtp or doveadm processes.

`login_source_ips`

Default	[None]
Value	Boolean List

A list of hosts / IP addresses that are used in a round-robin manner for the source IP address when the proxy creates TCP connections.

Example:

login_source_ips {
  proxy-sources.example.com = yes
}

`login_trusted_networks`

Default	[None]
Value	Boolean List

List of trusted IP addresses (e.g. 127.0.0.1 or ::1) or network ranges in CIDR notation (e.g. 192.168.0.0/24 or 2001:db8::/32).

This setting is used for a few different purposes, but most importantly it allows the client connection to tell the server what the original client's IP address was. This original client IP address is then used for logging and authentication checks.

Client connections from trusted networks are also treated as secured unless ssl = required. Plaintext authentication is always allowed for secured connections (auth_allow_cleartext is ignored).

Localhost connections are secured by default, but they are not trusted by default. If you want localhost to be trusted, it needs to be included in this setting.

The details of how this setting works depends on the used protocol:

IMAP

ID command can be used to override:

Session ID
Client IP and port (%{remote_ip}, %{remote_port})
Server IP and port (%{local_ip}, %{local_port})

forward_* fields can be sent to auth process's passdb lookup

The trust is always checked against the connecting IP address. Except if HAProxy is used, then the original client IP address is used.

POP3

XCLIENT command can be used to override:

Session ID
Client IP and port (%{remote_ip}, %{remote_port})
Added: 2.4.3 Server IP and port (%{local_ip}, %{local_port})

forward_* fields can be sent to auth process's passdb lookup

The trust is always checked against the connecting IP address. Except if HAProxy is used, then the original client IP address is used.

ManageSieve

XCLIENT command can be used to override:

Session ID
Client IP and port (%{remote_ip}, %{remote_port})
Added: 2.4.3 Server IP and port (%{local_ip}, %{local_port})

The trust is always checked against the connecting IP address. Except if HAProxy is used, then the original client IP address is used.

Submission

XCLIENT command can be used to override:

Session ID
Client IP and port (%{remote_ip}, %{remote_port})
HELO - Overrides what the client sent earlier in the EHLO command
LOGIN - Currently unused
PROTO - Currently unused
Added: 2.4.3 Server IP and port (%{local_ip}, %{local_port})

forward_* fields can be sent to auth process's passdb lookup

The trust is always checked against the connecting IP address. Except if HAProxy is used, then the original client IP address is used.

LMTP

XCLIENT command can be used to override:

Session ID
Client IP and port (%{remote_ip}, %{remote_port})
HELO - Overrides what the client sent earlier in the LHLO command
LOGIN - Currently unused
PROTO - Currently unused
TIMEOUT (overrides mail_max_lock_timeout)
Added: 2.4.3 Server IP and port (%{local_ip}, %{local_port})

The trust is always checked against the connecting IP address. Except if HAProxy is used, then the original client IP address is used.

`login_unauthenticated_client_limit`

Default	`unlimited`
Value	unsigned integer
See Also	`service_client_limit`
Changes	Added: 2.4.6

Maximum number of unauthenticated client connections in a single login process. unlimited means only service_client_limit limits them. 0 is not a valid value.

A connection is counted as unauthenticated from the moment it is accepted until the login has succeeded, including the time spent in TLS handshake and waiting for the auth process. Clients that have logged in and are being proxied by the login process are not counted.

When a new connection makes the count exceed the limit, the oldest unauthenticated client in the process is disconnected, the same way as when service_client_limit is reached. Clients that have already successfully authenticated and are waiting only for the post-login process are never disconnected. If there are no other clients that can be disconnected, the new client is disconnected. The disconnection is logged with the login_aborted event's unauthenticated_client_limit reason.

The limit is per login process, so the total limit for the service is service_process_limit multiplied by this value. Because of this, the setting can be configured globally, inside a protocol filter or inside a service filter. Client-specific filters, such as local and remote, are ignored. This setting is useful only with high performance login mode, where service_client_limit is large. It can be used to reduce the impact of DoS attacks that open many TCP connections without logging in.

`lua_file`

Default	[None]
Value	File
See Also	mail-lua plugin push-notification-lua plugin Lua authentication database

Path to lua script to be used. This is used by

`lua_settings`

Default	[None]
Value	String List
See Also	`lua_file`

Key-value pairs that are passed as a table to lua script_init() functions.

`mail_access_groups`

Default	`default_internal_group`
Value	Boolean List
See Also	`mail_privileged_group` `service_extra_groups`
Changes	Changed: 2.4.3 Changed from empty to `default_internal_group`.

Supplementary groups that are granted access for mail processes (imap, pop3, lmtp, etc.) The default is to include default_internal_group to allow UNIX socket access to various internal Dovecot services. For proper security, there should be no regular files or directories writable for the default_internal_group.

WARNING

It may be dangerous to use access groups if (untrusted) users can create symlinks to any paths the mail processes access.

For example if using mail_access_groups = mail:

ln -s /var/mail ~/mail/var could allow a user to delete others' mailboxes, or
ln -s /secret/shared/box ~/mail/mybox would allow reading others' mail.

`mail_alt_check`

Default	`yes`
Value	boolean
See Also	`mail_alt_path`

Whether to perform a sanity check and warn if mail_alt_path changes from the last access. This can catch accidentally broken configurations before users start reporting missing mails. The downside to this check is some additional disk IO.

`mail_alt_path`

Default	[None]
Value	directory path
See Also	dbox alternate storage
Changes	Changed: 2.4.6 Setting type changed.

Specifies the dbox alternate storage path.

Mail user variables and ~/ can be used.

`mail_always_cache_fields`

Default	[None]
Value	Boolean List
See Also	`mail_cache_fields` `mail_never_cache_fields`

The fields specified here are always added to cache when saving mails, even if the client never accesses these fields.

See mail cache configuration for details and for the list of fields.

`mail_attachment_detection_options`

Default	`- mbox, imapc, maildir: <empty> - others: add-flags content-type=!application/signature`
Value	Boolean List
Changes	Changed: 2.4.2 The default was set. Changed: 2.4.3 The Maildir default was reverted to empty.

Settings to control adding $HasAttachment or $HasNoAttachment keywords. By default, all MIME parts with Content-Disposition=attachment or inlines with filename parameter are considered attachments.

To enable this feature, this setting needs at least one option specified. Multiple options can be added in a space-separated list.

Options:

add-flags: Attachments are detected and marked during save. Detection is done also during fetch if it can be done without extra disk IO and with minimal CPU cost. This means that either both mime.parts and imap.bodystructure has to be in cache already, or if mail body is opened in any case.
add-flags no-flags-on-fetch: Flags are added during save, but not during fetch. This option will likely be removed in a later release.
content-type=<type|!type>: Include or exclude given content type. Including will only negate an exclusion (e.g. content-type=!foo/* content-type=foo/bar).
exclude-inlined: Do not consider any attachment with disposition inlined.

`mail_attribute`

Value	Named Filter
See Also	`imap_metadata`

Named filter for initializing dict driver for server and mailbox attributes (key=value).

This is used by the URLAUTH and METADATA extensions, as well as various other features.

Example:

mail_attribute {
  dict file {
    path = %{home}/dovecot-attributes
  }
}

`mail_cache_fields`

Default	`flags hdr.date hdr.subject hdr.from hdr.sender hdr.reply-to hdr.to hdr.cc hdr.bcc hdr.in-reply-to hdr.message-id date.received size.virtual imap.bodystructure mime.parts hdr.references hdr.importance hdr.x-priority hdr.x-open-xchange-share-url pop3.uidl pop3.order`
Value	Boolean List
See Also	`mail_always_cache_fields` `mail_never_cache_fields`
Changes	Changed: 2.4.1 The default fields were changed. They used to be just "flags".

The default list of fields that are added to cache if no other caching decisions exist yet. This setting is used only when creating the initial INBOX for the user. Other folders get their defaults from the INBOX.

See mail cache configuration for details and for the list of fields.

`mail_cache_path`

Default	`<same as mail_index_path setting>`
Value	directory path
Changes	Changed: 2.4.6 Setting type changed.

Place dovecot.index.cache files to this directory instead of among the other index files. This may be used as an optimization to split most index files to the fastest (smallest) storage while keeping cache files in a slightly slower (larger) storage.

Mail user variables and ~/ can be used.

`mail_chroot`

Default	[None]
Value	string

The default chroot directory for mail processes.

This chroots all users globally into the same directory.

Mail service user variables can be used.

`mail_compress_write_method`

Default	[None]
Value	string
Plugin	mail-compress plugin

The Compression Method to use for writing new mails. If empty, new mails are written without compression. Old mails can still be read.

`mail_control_path`

Default	[None]
Value	directory path
Changes	Changed: 2.4.6 Setting type changed.

Location for (mailbox-format specific) control files.

Mail user variables and ~/ can be used.

`mail_debug`

Default	`no`
Value	boolean

This setting adjusts log verbosity. It enables mail-process debugging. This can help you figure out the reason if Dovecot isn't finding certain mail messages.

`mail_driver`

Default	[None]
Value	string
See Also	Mailbox Formats Mailbox Root Autodetection `mail_path`

One of the mailbox formats described at Mailbox Formats.

For an empty value or auto, Dovecot attempts to find the mailboxes automatically.

`mail_ext_attachment`

Value	Named Filter
See Also	`fs_driver` `mail_ext_attachment_path`

Named filter for initializing FS Driver for external attachments.

Commonly used options:

posix

No single-instance storage (SIS) done (this option might simplify the filesystem's own de-duplication operations).

sis

SIS with immediate byte-by-byte comparison during saving.

SIS is deprecated and writing of SIS files is disabled. Reading is supported for now, any missing SIS attachments are replaced with files filled with spaces.

sis-queue

SIS with delayed comparison and de-duplication.

Changed: 2.4.0 SIS is deprecated and writing SIS files is disabled. Reading is supported for now. Any missing SIS attachments are replaced with files filled with spaces.

`mail_ext_attachment_min_size`

Default	`128k`
Value	size
See Also	`mail_ext_attachment_path`

Attachments below this size will not be saved externally.

`mail_ext_attachment_path`

Default	[None]
Value	directory path
Changes	Changed: 2.4.6 Setting type changed.

The directory in which to store mail attachments.

With sdbox and mdbox, mail attachments can be saved to external files, which also allows single-instance storage of them.

If no value is specified, attachment saving to external files is disabled.

Mail user variables and ~/ can be used.

`mail_fsync`

Default	`optimized`
Value	string
Allowed Values	`alwaysoptimizednever`

Specify when to use fsync() or fdatasync() calls.

Using fsync waits until the data is written to disk before it continues, which is used to prevent corruption or data loss in case of server crashes.

This setting applies to mail files and index files on the filesystem. This setting doesn't apply to object storage operations.

Options:

always

Use fsync after all disk writes.

Recommended for NFS to make sure there aren't any delayed write()s.

optimized

Use fsync after important disk writes.

For example cache file writes aren't fsynced, because they can be regenerated if necessary.

never

Never fsync any disk writes.

This provides the best performance, but risks losing recently saved emails in case of a crash with most mailbox formats.

`mail_gid`

Default	[None]
Value	stringunsigned integer
See Also	`mail_uid`

The system group ID used for accessing mail messages.

Can be either a numeric ID or a group name.

This can be overridden via the gid userdb field.

`mail_home`

Default	[None]
Value	string
See Also	`mail_path` Home Directories for Virtual Users

User's home directory. This is used as the root for some of the user-specific files and directories. The %{home} variable expands to this value. Also some path settings expand ~/ to this value.

There are various possible ways of specifying this parameter and mail_path.

The following example is one option when home is in /var/vmail/domain/user/ and mails are in /var/vmail/domain/user/mail/:

mail_home = /var/vmail/%{user | domain}/%{user | username}
mail_path = ~/mail

Mail service user variables can be used.

`mail_inbox_path`

Default	[None]
Value	directory path
See Also	`mail_home` `mail_path`
Changes	Changed: 2.4.6 Setting type changed.

Path to the INBOX mailbox. The path doesn't have to be absolute - it is relative to the mail_path.

WARNING

If your inbox does not reside in some weird location, you should not set this setting to any value.

Setting it to . or $MAIL_HOME/ will just cause problems.

You almost certainly want to change mail_home or mail_path settings instead.

This is often used with mbox format where INBOX is in /var/mail/ while the rest of the folders are under the user's home directory.

This can also be used to specify a different INBOX path with Maildir:

 mail_driver = maildir
 mail_path = ~/Maildir
 mail_inbox_path = ~/Maildir/.INBOX

Mail user variables and ~/ can be used.

`mail_index_path`

Default	`<same as mail_path setting>`
Value	directory path
See Also	Mail Location: Index Files
Changes	Changed: 2.4.6 Setting type changed.

Location of index files.

Mail user variables and ~/ can be used.

`mail_index_private_path`

Default	[None]
Value	directory path
See Also	public shared mailboxes
Changes	Changed: 2.4.6 Setting type changed.

The private index files are used with shared mailboxes to provide private (per-user) message flags.

Mail user variables and ~/ can be used.

`mail_log_cached_only`

Default	`no`
Value	boolean
Plugin	mail-log plugin

If enabled, everything except save event will log only the fields that can be looked up from cache. This improves performance if some of the fields aren't cached and it's not a strict requirement to log them.

`mail_log_events`

Default	[None]
Value	Boolean List
Plugin	mail-log plugin

List of events to log.

Available events:

delete
undelete
expunge
save
copy
mailbox_create
mailbox_delete
mailbox_rename
flag_change

`mail_log_fields`

Default	[None]
Value	Boolean List
Plugin	mail-log plugin

List of fields to log.

Field	Restrictions
`uid`
`box`
`msgid`
`size`	Only available for `expunge` and `copy` events.
`vsize`	Only available for `expunge` and `copy` events.
`vsize`
`flags`
`from`
`subject`

`mail_log_prefix`

Default	`%{service}(%{user})<%{process:pid}><%{session}>:`
Value	string

You can specify a log prefix for mail processes here.

Mail service user variables can be used.

`mail_lua`

Value	Named Filter
See Also	`lua_file` `lua_settings`
Plugin	mail-lua plugin
Changes	Added: 2.4.0

Named filter for initializing mail_lua plugin settings.

Example:

mail_lua {
  lua_file = /etc/dovecot/user.lua
  lua_settings {
    extra_param = %{userdb:extra_param}
  }
}

`mail_max_lock_timeout`

Default	`0`
Value	time

This value is used as a timeout for tempfailing mail connections. It can be set globally, for application to all Dovecot services, but is normally better to set it in only certain protocol blocks. You may wish to set a value for this for LMTP and LDA while leaving it at the global default of 0 for IMAP and POP3 connections, which tolerate tempfailing less well.

`mail_max_userip_connections`

Default	`10`
Value	unsigned integer

The maximum number of IMAP connections allowed for a user from each IP address.

This setting is checked only by backends, not proxies.

Note that for this to work, any username changes must be done already by passdb lookup (not by userdb lookup).

Unique users are identified via case-sensitive comparison.

`mail_never_cache_fields`

Default	`imap.envelope`
Value	Boolean List
See Also	`mail_always_cache_fields` `mail_cache_fields`

List of fields that should never be cached.

This should generally never include anything other than imap.envelope, which isn't needed because it can be generated from the cached header fields.

See mail cache configuration for details and for the list of fields.

`mail_nfs_index`

Default	`no`
Value	boolean
See Also	`mail_nfs_storage` `mail_fsync`

This setting attempts to flush NFS caches when accessing index files. The intention was that it would allow accessing the same user's index files in multiple servers at the same time. However, this couldn't be made to work perfectly due to the way Linux and BSD kernels work internally. The setting exists for now, but it is not a supported way of running Dovecot.

When using this setting, be sure also to use mmap_disable = yes and mail_fsync = optimized.

`mail_nfs_storage`

Default	`no`
Value	boolean
See Also	`mail_nfs_index`

This setting attempts to flush NFS caches when accessing mail storage. The intention was that it would allow accessing the same user's mails in multiple servers at the same time. However, this couldn't be made to work perfectly due to the way Linux and BSD kernels work internally. The setting exists for now, but it is not a supported way of running Dovecot.

`mail_path`

Default	`<specific to mail_driver setting>`
Value	directory path
See Also	Mail User Variables Home Directories for Virtual Users `mail_driver`
Changes	Changed: 2.4.6 Setting type changed.

Path to a directory where the mail is stored. Mail User Variables are commonly used here.

Usually the mails should be stored in a sub-directory under the home directory, but not the home directory itself (see Home Directories for Virtual Users).

The path must be absolute, not a relative path. Even if relative paths appear to work, this usage is deprecated and will likely stop working at some point.

Mail user variables and ~/ can be used.

`mail_plugin_dir`

Default	`/usr/lib64/dovecot`
Value	string
See Also	`mail_plugins`

The directory in which to search for Dovecot mail plugins.

`mail_plugins`

Default	[None]
Value	Boolean List
See Also	`mail_plugin_dir`

A list of mail plugins to load.

`mail_prefetch_count`

Default	[None]
Value	unsigned integer

The number of messages to try to prefetch whenever possible. 0 means that no prefetching is done. Depending on the (remote) storage latency, this may significantly speed up performance when reading many mails. The exact behavior depends on the mailbox format:

mbox, mdbox: No effect in behavior.
sdbox, Maildir: Call posix_fadvise(POSIX_FADV_WILLNEED) on mail files to instruct kernel to read the whole files into memory.
imapc: Combine multiple mail reads into the same remote imapc FETCH command. For example with mail_prefetch_count = 0 reading two mails would result in FETCH 1 BODY.PEEK[] and FETCH 2 BODY.PEEK[] commands, while with mail_prefetch_count = 1 they would be combined into a single FETCH 1:2 BODY.PEEK[] command. The downside is that each mail uses a file descriptor and disk space in mail_temp_dir. A good value is likely between 10..100.

`mail_privileged_group`

Default	[None]
Value	string
See Also	`mail_access_groups`

This group is enabled temporarily for privileged operations. Currently, this is used only with the mbox format with INBOX when either its initial creation or dotlocking fails.

Typically, this is set to mail to give access to /var/mail when using the mbox format.

You can give Dovecot access to mail group by setting mail_privileged_group = mail.

`mail_server_admin`

Default	[None]
Value	string
See Also	`imap_metadata`

The method for contacting the server administrator.

Per the METADATA standard (RFC 5464), this value MUST be a URI (e.g., a mailto: or tel: URL), but that requirement is not enforced by Dovecot.

This value is accessible to authenticated users through the /shared/admin IMAP METADATA server entry.

Example:

mail_server_admin = mailto:admin@example.com

`mail_server_comment`

Default	[None]
Value	string
See Also	`imap_metadata`

A comment or note that is associated with the server.

This value is accessible to authenticated users through the /shared/comment IMAP METADATA server entry.

`mail_shared_explicit_inbox`

Default	`no`
Value	boolean

This setting determines whether a shared INBOX should be visible as "shared/user" or as "shared/user/INBOX" instead.

`mail_sort_max_read_count`

Default	`unlimited`
Value	unsigned integer

The number of slow mail accesses an IMAP SORT can perform before it returns failure to the client.

On failure, the untagged SORT reply is retuned, but it is likely not correct.

The IMAP reply returned to the client is:

NO [LIMIT] Requested sort would have taken too long.

`mail_temp_dir`

Default	`/tmp`
Value	string

The directory in which LDA/LMTP will temporarily store incoming message data that is above 128kB in size.

Mail user variables can be used.

`mail_temp_scan_interval`

Default	`1week`
Value	time

How often Dovecot scans for and deletes stale temporary files. These files exist only if Dovecot crashes while saving a message. This is just to make sure such temporary files will eventually get deleted to avoid wasting disk space. This scan happens independently for each folder, and it's done at the time the folder is opened.

In order to prevent load spikes, the actual value of the setting is spread increasing it by 0..30%, based on a hash of the username.

The scanning is done only for these mailbox formats:

Maildir: Delete all files having ctime older than 36 hours from tmp/. The scan is done if tmp/ directory's atime older than this setting.
sdbox, mdbox: Delete .temp.* files having ctime older than 36 hours from dbox-Mails/. The scan is done if the last_temp_file_scan header field in dovecot.index is older than this setting.
mdbox: Delete .temp.* files having ctime older than 36 hours from storage/. The scan is done if storage/ directory's atime is older than this setting.

A value of 0 means this scan never occurs.

`mail_uid`

Default	[None]
Value	stringunsigned integer
See Also	`mail_gid`

This setting indicates the system userid used for accessing mail messages.

Can be either a numeric ID or a username.

This can be overridden via the uid userdb field.

`mail_utf8_extensions`

Default	`no`
Value	boolean

If Dovecot has been compiled with --enable-experimental-mail-utf8 configure option, this setting can be used to enable the feature. Settings this to yes will enable SMTPUTF8 for LMTP and Submission sessions, and UTF8=ACCEPT for IMAP sessions.

`mail_volatile_path`

Default	[None]
Value	directory path
Changes	Changed: 2.4.6 Setting type changed. Changed: 2.4.5 Fixed behavior to avoid collisions across multiple namespaces.

Specifies the location of volatile files. This includes lock files and potentially other files that don't need to exist permanently, so it can point to an in-memory filesystem (tmpfs). This is especially useful to avoid creating lock files to NFS or other remote filesystems.

This setting can be shared between multiple namespaces. Dovecot makes the filenames unique for each namespace to avoid collisions.

Mail user variables and ~/ can be used.

`mail_vsize_bg_after_count`

Default	`unlimited`
Value	unsigned integer
See Also	quota plugin

Controls transitioning mail size determination to the background instead of synchronously during the delivery process.

After this many messages have been opened, the system allows a background indexer-worker process to perform quota calculations in the background.

This may happen when mail messages do not have their virtual sizes cached.

When indexing is occurring in the background, explicit quota size queries return an internal error and mail deliveries are assumed to succeed.

This setting must not be set to indexer-worker process, or the background calculation isn't finished. The configuration should be like:

protocol !indexer-worker {
  mail_vsize_bg_after_count = 10
}

`mailbox`

Default	[None]
Value	Named List Filter

Create a new mailbox to the list of mailboxes. The filter name refers to the mailbox_name setting.

The mailbox name can contain ? and * wildcards. Settings are applied for all matching mailbox filters.

TIP

If the mailbox name has spaces, you can put it into quotes:

mailbox "Test Mailbox" {
  # ...
}

TIP

It's possible to rename the mailbox in userdb. For example:

mailbox junk {
  name = Junk
  special_use = \Junk
}

The userdb can then return mailbox/junk/name=Spam to rename the mailbox for a specific user.

`mailbox_auto`

Default	`no`
Value	string
Allowed Values	`createnosubscribe`

Autocreate and/or subscribe to the mailbox?

Value	Description
`create`	Autocreate but don't autosubscribe
`no`	Don't autocreate or autosubscribe
`subscribe`	Autocreate and autosubscribe

Autocreated mailboxes are created lazily to disk only when accessed for the first time. The autosubscribed mailboxes aren't written to subscriptions file, unless SUBSCRIBE command is explicitly used for them.

`mailbox_autoexpunge`

Default	[None]
Value	time
See Also	`mailbox_autoexpunge_max_mails`

Expunge all mails in this mailbox whose saved-timestamp is older than this value. 0 means autoexpunging is disabled.

For IMAP and POP3 this happens after the client is already disconnected.

For LMTP this happens when the user's mail delivery is finished. Note that in case there are multiple recipients, autoexpunging is done only for some of the recipients to prevent delays with the mail delivery: The last recipient user is autoexpunged first. Next, the first recipient user is autoexpunged (because the first user's mail was kept open in case it could be directly copied to the other users). None of the middle recipient users are autoexpunged.

mailbox_list_index = yes is highly recommended when using this setting, as it avoids actually opening the mailbox to see if anything needs to be expunged.

mail_always_cache_fields = date.save is also recommended when using this setting with sdbox or Maildir, as it avoids using stat() to find out the mail's saved-timestamp. With mdbox format this isn't necessary, since the saved-timestamp is always available.

`mailbox_autoexpunge_max_mails`

Default	[None]
Value	unsigned integer

Mails are autoexpunged until mail count is at or below this number of messages.

Once this threshold has been reached, mailbox_autoexpunge processing is done.

`mailbox_directory_name`

Default	`<specific to mail_driver setting>`
Value	string
See Also	`mail_driver` `mailbox_directory_name_legacy`

Specifies the directory name used for mailbox, index, and control directory paths. See the individual mailbox format pages for further information. For example dbox-Mails with dbox.

With mbox format this works differently. The user-provided mailbox name is the directory name, while mailbox_directory_name is the mbox file. For example with mailbox_directory_name=mbox, creating foo/bar mailbox name ends up creating .../foo/bar/mbox file.

`mailbox_directory_name_legacy`

Default	`no`
Value	boolean
See Also	`mailbox_directory_name`
Changes	Changed: 2.4.2 The default value changed from `yes` to `no`. Deprecated: 2.4.2 This legacy setting is obsolete and destined to be removed. Changing this setting requires migration, see dbox: Migrating away from `mailbox_directory_name_legacy`

If no, mailbox_directory_name applies also to index and control directories. The only reason to set this to yes is if you already have an existing Dovecot installation with the legacy DIRNAME (rather than FULLDIRNAME) parameter and don't want to migrate the data.

`mailbox_list_drop_noselect`

Default	`yes`
Value	boolean

Specifies whether to automatically delete NoSelect mailboxes that have no children. These mailboxes are sometimes confusing to users. Also if a NoSelect mailbox is attempted to be created with CREATE box/, it's created as selectable mailbox instead.

INFO

Maildir layout does not support NoSelect mailboxes, so this setting has no effect with it.

`mailbox_list_index`

Default	`yes`
Value	boolean

Dovecot indexes live at the root of user's mailbox storage, and allows quick lookup of mailbox status instead of needing to open all mailbox indexes separately.

Enabling this optimizes the server reply to IMAP STATUS commands, which are commonly issued by clients. This also needs to be enabled if you wish to enable the IMAP NOTIFY extension.

`mailbox_list_index_include_inbox`

Default	`no`
Value	boolean
See Also	`mailbox_list_index`

Should INBOX be kept up-to-date in the mailbox list index?

Disabled by default as most mailbox accesses will open INBOX anyway.

`mailbox_list_index_prefix`

Default	`dovecot.list.index`
Value	string

Prefix for the mailbox list index filename. It may also optionally include a path (relative to mail_index_path) to place it in a different directory.

`mailbox_list_index_very_dirty_syncs`

Default	`no`
Value	boolean

If enabled, assume that the mailbox list index is fully updated so that stat() will not be run for mailbox files/directories.

`mailbox_list_iter_from_index_dir`

Default	`no`
Value	boolean

Perform mailbox listing using the mail_index_path directories instead of the mail_path directories. Mainly useful when the index file storage is on a faster storage.

`mailbox_list_layout`

Default	`fs`
Value	string
Allowed Values	`fsindexMaildir++`
See Also	dbox Maildir mbox

Directory layout to use.

Value	Description
`Maildir++`	The default used by Maildir.
`fs`	The default used by mbox and dbox.
`index`	Uses mailbox GUIDs as the directory names. The mapping between mailbox names and GUIDs exists in `dovecot.list.index*` files.

INFO

The mail_driver setting provides the default value, that the mailbox_list_layout setting can override.

`mailbox_list_storage_escape_char`

Default	The default for imapc storage is `%`.
Value	string
See Also	`mailbox_list_visible_escape_char`

Specifies an escape character that it used for encoding special characters in the mailbox names in storage. This allows users to use characters in mailboxes names that would otherwise be illegal. For example:

Maildir layout disallows using the . character, since it's used internally as the folder hierarchy separator.
The ~ character at the beginning of the mailbox name is disallowed, because of the possibility that it gets expanded to user's home directory.
The / character can't be used on POSIX filesystems, since it's the directory separator.

The characters are escaped to the mailbox name as <mailbox_list_storage_escape_char><hex>.

INFO

It's possible to use the same character here as for mailbox_list_visible_escape_char.

`mailbox_list_utf8`

Default	`no`
Value	boolean

Store mailbox names on disk using UTF-8 instead of modified UTF-7 (mUTF-7). This applies also to the mailbox list index with mailbox_list_layout = index.

WARNING

Changing this breaks already existing non-ASCII mailbox names.

`mailbox_list_validate_fs_names`

Default	`yes`
Value	boolean
See Also	`mail_full_filesystem_access`

Specifies whether to disallow mailbox names that might be unsafe to use in filesystems or potentially allow bypassing ACL checks:

/ character anywhere in the name (except as a hierarchy separator), unless mailbox list isn't on a filesystem (e.g. index, imapc).
/ as the first character.
~ as the first character (so it's not confused as home directory).
No adjacent / characters.
No . or .. names between / characters.
No mailbox_directory_name between / characters.
No mailbox format-specific internal directories between / characters,
unless mailbox_directory_name is non-empty. This mainly means the Maildir new, cur and tmp directories in some configurations.

Enabling mail_full_filesystem_access enables also this setting.

`mailbox_list_visible_escape_char`

Default	The default for imapc storage is `~`.
Value	string
See Also	`mailbox_list_storage_escape_char`

Specifies an escape character that is used for broken or otherwise inaccessible mailbox names. If mailbox name can't be changed reversibly to UTF-8 and back, encode the problematic parts using <mailbox_list_visible_escape_char><hex>in the user-visible UTF-8 name. The mailbox_list_visible_escape_char itself also has to be encoded the same way.

This can be useful with imapc to access mailbox names that aren't valid mUTF-7 charset from remote servers, or if the remote server uses a different hierarchy separator and has folder names containing the local separator.

INFO

It's possible to use the same character here as for mailbox_list_storage_escape_char.

`mailbox_name`

Default	[None]
Value	string

Name of the mailbox being configured. The mailbox filter name refers to this setting.

`mailbox_notify_status`

Default	`no`
Value	boolean
Plugin	notify-status plugin

Whether notifications for a single mailbox or mailbox wildcards are enabled.

Example:

mailbox INBOX {
  notify_status = yes
}
mailbox Spam {
  notify_status = yes
}
mailbox *BOX {
  notify_status = yes
}

`mailbox_root_directory_name`

Default	`specific to the mail_driver setting`
Value	string

Specifies directory name under which all mailbox directories are stored. For example mailboxes with dbox.

`mailbox_special_use`

Default	[None]
Value	Boolean List
See Also	Namespaces
Changes	Changed: 2.4.0 Using non-standard special-use flags will result in a warning message at startup.

List of SPECIAL-USE (RFC 6154) flags to broadcast for the mailbox.

There are no validity checks, so you could specify anything you want here, but it's not a good idea to use other than the standard ones specified in the RFC.

`maildir_broken_filename_sizes`

Default	`no`
Value	boolean
See Also	Maildir

If enabled, do not obtain a mail message's physical size from the S=<size> data in the Maildir filename except when recalculating the Maildir++ quota.

`maildir_copy_with_hardlinks`

Default	`yes`
Value	boolean
See Also	Maildir

If enabled, copying of a message is done with hard links whenever possible.

This makes the performance much better, and it's unlikely to have any side effects. The only reason to disable this is if you're using a filesystem where hard links are slow (e.g. HFS+).

`maildir_empty_new`

Default	`no`
Value	boolean
See Also	Maildir

Should mail messages always be moved from the new/ directory to cur/, even when the Recent flags aren't being reset?

`maildir_stat_dirs`

Default	`no`
Value	boolean
See Also	Maildir

If enabled, don't include non-directory files in a LIST response that begin with a dot. Thus, if disabled, Dovecot assumes that all the files beginning with a dot in the Maildir are Maildirs.

You shouldn't have any non-directory files beginning with a dot in the Maildirs, but if you do you may need to set this to yes, in which case Dovecot needs to stat() each directory entry, which degrades the performance. Some filesystems (e.g. ext4) provide the directory/non-directory status for free without having to stat(). In those filesystems this setting is ignored.

`maildir_very_dirty_syncs`

Default	`no`
Value	boolean
See Also	Maildir

If enabled (yes), Dovecot is assumed to be the only MUA that accesses Maildir directly, so the cur/ directory is scanned only when its mtime changes unexpectedly or when the mail cannot otherwise be found.

If enabled and another process (or a Dovecot process which doesn't update index files) does changes to cur/ while the mailbox is simultaneously being modified by Dovecot, Dovecot may not notice those external changes.

It is still safe to deliver new mails to new/ using non-Dovecot software (except with mailbox_list_index = yes, changes aren't noticed outside INBOX).

`managesieve_logout_format`

Default	`bytes=%{input}/%{output}`
Value	String without variables

Specifies the string pattern used to compose the logout message of an authenticated session. The following substitutions are available:

Variable Name	Description
`%{input}`	Total number of bytes read from client
`%{output}`	Total number of bytes sent to client
`%{put_count}`	Number of scripts uploaded by client using PUTSCRIPT command
`%{put_bytes}`	Number of bytes with script data sent by client using PUTSCRIPT command
`%{get_count}`	Number of scripts downloaded by client using GETSCRIPT command
`%{get_bytes}`	Number of bytes with script data sent to client using GETSCRIPT command
`%{check_count}`	Number of scripts checked by client using CHECKSCRIPT command
`%{check_bytes}`	Number of bytes with script data sent by client using CHECKSCRIPT command
`%{deleted_count}`	Number of scripts deleted by client using DELETESCRIPT command
`%{renamed_count}`	Number of scripts renamed by client using RENAMESCRIPT command
`%{session}`	The client session ID

`mbox_dirty_syncs`

Default	`yes`
Value	boolean
See Also	`mbox_very_dirty_syncs` mbox

Enable optimized mbox syncing?

For larger mbox files, it can take a long time to determine what has changed when the file is altered unexpectedly. Since the change in most cases consists solely of newly appended mail, Dovecot can operate more quickly if it starts off by simply reading the new messages, then falls back to reading the entire mbox file if something elsewhere in it isn't as expected.

Dovecot assumes that external mbox file changes only mean that new messages were appended to it. Without this setting Dovecot re-reads the whole mbox file whenever it changes. There are various safeguards in place to make this setting safe even when other changes than appends were done to the mbox. The downside to this setting is that external message flag modifications may not be visible immediately.

When this setting is enabled, Dovecot tries to avoid re-reading the mbox every time something changes. Whenever the mbox changes (i.e. timestamp or size), Dovecot first checks if the mailbox's size changed. If it didn't, it most likely meant that only message flags were changed so it does a full mbox read to find it. If the mailbox shrunk, it means that mails were expunged and again Dovecot does a full sync. Usually however the only thing besides Dovecot that modifies the mbox is the LDA which appends new mails to the mbox. So if the mbox size was grown, Dovecot first checks if the last known message is still where it was last time. If it is, Dovecot reads only the newly added messages and goes into "dirty mode". As long as Dovecot is in dirty mode, it can't be certain that mails are where it expects them to be, so whenever accessing some mail, it first verifies that it really is the correct mail by finding its X-UID header. If the X-UID header is different, it fallbacks to a full sync to find the mail's correct position. The dirty mode goes away after a full sync. If mbox_lazy_writes was enabled and the mail didn't yet have an X-UID header, Dovecot uses the MD5 sum of a couple of headers to compare the mails.

`mbox_dotlock_change_timeout`

Default	`2 mins`
Value	time
See Also	mbox

Override a lockfile after this amount of time if a dot-lock exists but the mailbox hasn't been modified in any way.

`mbox_lazy_writes`

Default	`yes`
Value	boolean
See Also	mbox

If enabled, mbox headers (e.g., metadata updates, such as writing X-UID headers or flag changes) are not written until a full write sync is performed (triggered via IMAP EXPUNGE or CHECK commands and/or when the mailbox is closed). mbox rewrites can be costly, so this may avoid a lot of disk writes.

Enabling this setting is especially useful with POP3, in which clients often delete all mail messages.

One negative consequence of enabling this setting is that the changes aren't immediately visible to other MUAs.

C-Client works the same way. The upside of this is that it reduces writes because multiple flag updates to same message can be grouped, and sometimes the writes don't have to be done at all if the whole message is expunged. The downside is that other processes don't notice the changes immediately (but other Dovecot processes do notice because the changes are in index files).

`mbox_lock_timeout`

Default	`5 mins`
Value	time
See Also	mbox

The maximum time to wait for all locks to be released before aborting.

`mbox_read_locks`

Default	`fcntl`
Value	Boolean List
Allowed Values	`dotlockdotlock_tryfcntlflocklockf`
See Also	mbox

Specify which locking method(s) to use for locking the mbox files during reading.

Descriptions of the locking methods can be found at mbox locking.

`mbox_very_dirty_syncs`

Default	`no`
Value	boolean
See Also	`mbox_dirty_syncs` mbox

If enabled, Dovecot performs the optimizations from mbox_dirty_syncs also for the IMAP SELECT, EXAMINE, EXPUNGE, and CHECK commands.

If set, this option overrides mbox_dirty_syncs.

`mbox_write_locks`

Default	`dotlock fcntl`
Value	Boolean List
Allowed Values	`dotlockdotlock_tryfcntlflocklockf`
See Also	mbox

Specify which locking method(s) to use for locking the mbox files during writing.

Descriptions of the locking methods can be found at mbox locking.

`mdbox_preallocate_space`

Default	`no`
Value	boolean
See Also	`mdbox_rotate_size` mdbox

mdbox only: If enabled, preallocate space for newly created files.

In creation of new mdbox files, their size is immediately preallocated as mdbox_rotate_size.

This setting currently works only in Linux with certain filesystems (ext4 and xfs).

`mdbox_rotate_interval`

Default	[None]
Value	size
See Also	mdbox

mdbox only: The maximum age the dbox file may reach before it's rotated.

0 means there is no age-based rotation.

`mdbox_rotate_size`

Default	`10M`
Value	size
See Also	mdbox

mdbox only: The maximum size the dbox file may reach before it is rotated.

`metric`

Default	[None]
Value	Named List Filter
See Also	`metric_name`

Creates a new metric. The filter name refers to the metric_name setting.

`metric_description`

Default	[None]
Value	string

Human-readable description of the metric. This is included in the HELP text sent to OpenMetrics.

`metric_exporter`

Default	[None]
Value	string
See Also	Event Export `event_exporter_name`

Export events matching the filter with this event exporter. Refers to the event_exporter_name setting. If empty, the events are used only for statistics, and no exporting is done.

`metric_exporter_include`

Default	`name hostname timestamps categories fields`
Value	Boolean List

Specifies which parts of the event are exported to the serialized event:

Values	Description
`name`	The name of the event.
`hostname`	The name of the host generating this event.
`timestamps`	The event start and end timestamps.
`categories`	A set of categories associated with this event.
`fields`	The fields associated with this event. The fields that will be exported are defined by the `metric_fields` setting.

For example:

metric example {
  exporter_include = name hostname timestamps
}

includes just the 3 specified parts, while

metric another_example {
  exporter_include =
}

includes nothing and the exported event will be empty (i.e. {} in JSON).

`metric_fields`

Default	[None]
Value	Boolean List
Changes	Changed: 2.4.0 All listed fields are exported to OpenMetrics as well.

A list of fields included in the metric. All events have a default duration field that does not need to be listed explicitly.

`metric_filter`

Default	[None]
Value	string
See Also	Metric Filters

Event filter that matches the events belonging to this metric.

`metric_group_by`

Default	[None]
Value	Named List Filter
See Also	Statistics: Group By

Creates a new group_by for dynamically generating sub-metrics based on the specified field's values. The filter name refers to the metric_group_by_field.

`metric_group_by_field`

Default	[None]
Value	string
See Also	Statistics: Group By

Generate sub-metrics based on this event field name. The metric_group_by filter name refers to this setting.

WARNING

Avoid high-cardinality fields. Each distinct value creates a sub-metric kept in memory with no upper limit, so fields like usernames, email addresses, remote IPs, message IDs, or mailbox GUIDs will cause unbounded memory growth. Use low-cardinality fields, or reduce cardinality with the exponential/linear aggregation methods or metric_group_by_method_discrete_modifier.

`metric_group_by_method`

Default	[None]
Value	Named List Filter
See Also	Statistics: Group By

Configures metric_group_by_method_method = the aggregation method for the metric_group_by. Only a single method can be specified for a group_by. The filter name refers to the metric_group_by_method_method.

`metric_group_by_method_discrete_modifier`

Default	[None]
Value	String without variables
See Also	Statistics: Group By

Configures a modifier string for values grouped by the discrete method. %variables and their functions can be used:

%{value}: The original value.
%{user | domain}: If the value is in user@domain format, this contains the domain text. Otherwise empty.

`metric_group_by_method_exponential_base`

Default	`10`
Value	unsigned integer
See Also	Statistics: Group By `metric_group_by_method_exponential_min_magnitude` `metric_group_by_method_exponential_max_magnitude`

Configures the base for values grouped by the exponential method. Only 2 and 10 are supported.

`metric_group_by_method_exponential_max_magnitude`

Default	[None]
Value	unsigned integer
See Also	Statistics: Group By `metric_group_by_method_exponential_min_magnitude` `metric_group_by_method_exponential_base`

Configures the maximum magnitude for values grouped by the exponential method.

Changed: 2.4.6 The maximum value is 62 with metric_group_by_method_exponential_base = 2 and 18 with metric_group_by_method_exponential_base = 10.

`metric_group_by_method_exponential_min_magnitude`

Default	[None]
Value	unsigned integer
See Also	Statistics: Group By `metric_group_by_method_exponential_max_magnitude` `metric_group_by_method_exponential_base`

Configures the minimum magnitude for values grouped by the exponential method.

Changed: 2.4.6 Must be smaller than metric_group_by_method_exponential_max_magnitude.

`metric_group_by_method_linear_max`

Default	[None]
Value	unsigned integer
See Also	Statistics: Group By `metric_group_by_method_linear_min` `metric_group_by_method_linear_step`

Configures the maximum for values grouped by the linear method.

`metric_group_by_method_linear_min`

Default	[None]
Value	unsigned integer
See Also	Statistics: Group By `metric_group_by_method_linear_max` `metric_group_by_method_linear_step`

Configures the minimum for values grouped by the linear method.

`metric_group_by_method_linear_step`

Default	[None]
Value	unsigned integer
See Also	Statistics: Group By `metric_group_by_method_linear_min` `metric_group_by_method_linear_max`

Configures the step for values grouped by the linear method.

`metric_group_by_method_method`

Default	`discrete`
Value	string
Allowed Values	`discreteexponentiallinear`
See Also	Statistics: Group By

Configures the aggregation method for the metric_group_by. The metric_group_by_method filter name refers to this setting.

`metric_name`

Default	[None]
Value	string

Name of the metric. It is visible in statistics outputs. The metric filter name refers to this setting.

`mmap_disable`

Default	`no`
Value	boolean

Disable mmap() usage?

This must be set to yes if you store indexes to shared filesystems (i.e., if you use NFS or a clustered filesystem).

`mysql`

Default	[None]
Value	Named List Filter
See Also	`mysql_host`

Creates a new MySQL/MariaDB connection. If more than one is specified, the connections are automatically used for load balancing and for failover. The filter name refers to the mysql_host setting.

`mysql_client_flags`

Default	[None]
Value	unsigned integer

Flags to use when connecting to the database, provided as base-10 number. See https://dev.mysql.com/doc/c-api/8.0/en/mysql-real-connect.html

`mysql_connect_timeout`

Default	`5s`
Value	time

How long to wait for connection.

`mysql_connection_limit`

Default	`5`
Value	unsigned integer

Maximum number of parallel connections. Currently MySQL queries are blocking, so only a single connection can be used in parallel.

`mysql_dbname`

Default	[None]
Value	string

Database name to connect to.

`mysql_host`

Default	`localhost`
Value	string

Host or UNIX socket path to connect to. The mysql setting defaults to this.

INFO

MySQL drivers can default to using UNIX socket connection when host is localhost and port is 0 (default). To force it to use TCP connection, set mysql_host = 127.0.0.1 or set mysql_port explicitly.

`mysql_option_file`

Default	[None]
Value	string

File to read for client library specific configuration.

`mysql_option_group`

Default	[None]
Value	string

Section name to read from mysql_option_file.

`mysql_password`

Default	[None]
Value	string

Password for authentication.

`mysql_port`

Default	`0 (defaults to 3306 for TCP connections)`
Value	Port Number

Port to connect to.

`mysql_read_timeout`

Default	`30s`
Value	time

Timeout when reading data from server.

`mysql_ssl`

Default	`no`
Value	boolean
See Also	SSL

Whether to use SSL when connecting to MySQL. Configure it using the ssl_client_* settings. See SSL.

`mysql_user`

Default	[None]
Value	string

Username for authentication.

`mysql_write_timeout`

Default	`30s`
Value	time

Timeout in seconds when writing data to server.

`namespace`

Default	[None]
Value	Named List Filter

Creates a new namespace to the list of namespaces. The filter name refers to the namespace_name setting.

Example:

namespace foo {
  [...]
}

`namespace_alias_for`

Default	[None]
Value	string

Refers to an alias namespace's namespace_name.

If multiple namespaces point to the same location, they should be marked as aliases against one primary namespace. This avoids duplicating work for some commands (listing the same mailbox multiple times).

Mail user variables can be used.

Note: Alias namespaces often have hidden=yes and list=no so they are not visible unless clients have specifically configured them, and they're typically used when migrating to a different namespace prefix for existing users.

Example:

namespace inbox {
  prefix =
  # ...
}
namespace alias {
  prefix = INBOX/
  alias_for = inbox
}

`namespace_disabled`

Default	`no`
Value	boolean

If yes, namespace is disabled and cannot be accessed by user in any way.

Useful when returned by a userdb lookup to easily configure per-user namespaces.

`namespace_hidden`

Default	`no`
Value	boolean

If yes, namespace will be hidden from IMAP NAMESPACE (RFC 2342) command.

`namespace_ignore_on_failure`

Default	`no`
Value	boolean

If namespace's storage initialization fails, by default the entire session will fail to start. If this is set, this namespace will be ignored instead.

`namespace_inbox`

Default	`no`
Value	boolean

If yes, this namespace will be considered the one holding the INBOX folder.

There can be only one namespace defined like this.

`namespace_list`

Default	`yes`
Value	string
Allowed Values	`yesnochildren`
See Also	`namespace_hidden`

Include this namespace in LIST output when listing its parent's folders.

Options:

Value	Description
`children`	Namespace prefix list listed only if it has child mailboxes.
`no`	Namespace and mailboxes not listed unless listing requests explicitly mailboxes under the namespace prefix.
`yes`	Namespace and mailboxes are always listed.

It is still possible to list the namespace's folders by explicitly asking for them. For example, if this setting is no, using LIST "" * with namespace prefix "lazy-expunge/" won't list it, but using LIST "" lazy-expunge/* lists all folders under it.

`namespace_name`

Default	[None]
Value	string

Name of the namespace. This is used only in configurations - it's not visible to user. The namespace filter refers to this setting.

`namespace_order`

Default	[None]
Value	unsigned integer

Sets display order in IMAP NAMESPACE (RFC 2342) command.

Namespaces are automatically numbered if this setting does not exist.

`namespace_prefix`

Default	[None]
Value	string

Specifies prefix for namespace.

INFO

Must end with namespace_separator.

Mail user variables can be used.

Example:

namespace shared {
  prefix = Shared/
  separator = /
}

`namespace_separator`

Default	`"." for Maildir; "/" for other mbox formats`
Value	string
See Also	Namespaces: Hierarchy Separators

Specifies the hierarchy separator for the namespace.

The separator is a single character, which can't then otherwise be used in folder names.

The commonly used separators are . and /, but other separators can be used as well. For example ^ is less likely to be found in normal folder names.

Recommended value is to leave it empty and accept the default value.

`namespace_subscriptions`

Default	`yes`
Value	boolean

Whether subscriptions are stored in this namespace.

This is usually no for shared namespaces so that the shared folders' subscriptions are stored in the user's primary subscriptions file. If no, the subscriptions are stored in the first parent namespace (based on the prefix) that has this setting enabled.

Example: If this setting is no for a namespace with prefix=foo/bar/, Dovecot first sees if there's a prefix=foo/ namespace with subscriptions=yes and then a namespace with an empty prefix. If neither is found, an error is given.

`namespace_type`

Default	`private`
Value	string
Allowed Values	`privatesharedpublic`

The namespace type. One of:

Type	Description
`public`	Contains public shared mailboxes.
`private`	Typically contains only user's own private mailboxes.
`shared`	Contains other users' user shared mailboxes.

`notify_status`

Default	[None]
Value	string
Dependencies	dictionary
Plugin	notify-status plugin

The URI of the dictionary to use. This MUST be set for the plugin to be active.

See dictionary for how to configure dictionaries.

notify_status {
  dict proxy {
    name = notify_status
    socket_path = dict-async
  }
}

`notify_status_value`

Default	`{"messages":%{messages},"unseen":%{unseen}}`
Value	String without variables
Plugin	notify-status plugin

A template of the string that will be written to the dictionary.

The template supports variable substitution of the form %{variable_name}.

Supported variable substitutions:

Field	Value
`first_recent_uid`	First recent UID
`highest_modseq`	Highest modification sequence number
`highest_pvt_modseq`	Highest private modification sequence number
`mailbox`	Mailbox name
`messages`	Number of messages
`recent`	Number of recent messages (deprecated)
`uidnext`	Predicted next UID value
`uidvalidity`	Current UID validity
`unseen`	Number of unseen messages
`username`	Username (user@domain)

`oauth2`

Value	Named Filter
See Also	OAuth2 Authentication Database

Filter for oauth2 specific settings.

`oauth2_active_attribute`

Default	[None]
Value	string

Attribute name for (optional) checking whether account is disabled.

`oauth2_active_value`

Default	[None]
Value	string

Expected value in active_attribute. (empty = require present, but anything goes)

`oauth2_fields`

Default	[None]
Value	String List

Key-value fields to include in successful authentication.

`oauth2_force_introspection`

Default	`no`
Value	boolean

Force introspection even if tokeninfo contains wanted fields. Set this to yes if you are using oauth2_active_attribute.

`oauth2_introspection_mode`

Default	[None]
Value	string
Allowed Values	`<empty>authgetpostlocal`
See Also	`oauth2_introspection_url` `oauth2_tokeninfo_url` `oauth2_force_introspection`

To enable oauth2 you must choose how to do token introspection. oauth2_introspection_url is not required if oauth2_tokeninfo_url already provides all the necessary fields, or if you are using local validation.

You can force introspection with oauth2_force_introspection, if you need to it every time.

With local validation, oauth2_tokeninfo_url is also ignored.

Value	Description
`auth`	GET request with Bearer authentication.
`get`	GET request with token appended to URL.
`post`	POST request with token=bearer_token as content.
`local`	Attempt to locally validate and decode JWT token.

`oauth2_introspection_url`

Default	[None]
Value	string

URL for getting more information about token.

`oauth2_issuers`

Default	[None]
Value	Boolean List

Valid issuer(s) for the token.

`oauth2_local_validation`

Value	Named Filter
See Also	`dict`

A dictionary for fetching validation keys.

Example:

oauth2_local_validation {
  dict fs {
    fs posix {
      prefix = /tmp/keys/
    }
  }
}

`oauth2_openid_configuration_url`

Default	[None]
Value	string

URL to RFC 7628 OpenID Provider Configuration Information schema.

`oauth2_scope`

Default	[None]
Value	Boolean List

A list of valid scopes.

`oauth2_send_auth_headers`

Default	`no`
Value	boolean

Whether to send special headers about authentication to remote server. If you enable this, the following headers will be sent:

X-Dovecot-Auth-Protocol: Requested protocol, such as imap or pop3.
X-Dovecot-Auth-Local: Local IP address where client connected to.
X-Dovecot-Auth-Remote: Remote IP address of the client connection.

`oauth2_token_expire_grace`

Default	`1min`
Value	time

Specifies how long after token expiration it is still accepted. It shouldn't be 0 because clocks aren't exact, and network can add some delays.

`oauth2_tokeninfo_url`

Default	[None]
Value	string

URL for verifying token validity. Token is appended to the URL.

Example:

oauth2_tokeninfo_url = http://endpoint/oauth/tokeninfo?access_token=

`oauth2_use_worker_with_mech`

Default	`no`
Value	boolean
See Also	`passdb_use_worker`

Use worker process to verify token. This setting only applies to mechanism. If you want to use worker with passdb oauth2, use passdb_use_worker instead. Worker processes are mostly useful for distributing local token validation to multiple CPUs.

`oauth2_username_attribute`

Default	`email`
Value	string

Username attribute in response.

`oauth2_username_validation_format`

Default	`%{user}`
Value	string
See Also	`oauth2_username_attribute`

Normalization for oauth2 provided username, this setting is normally not needed. You only need this if the username that comes from authentication will not otherwise match with oauth2_username_attribute value.

`passdb`

Default	[None]
Value	Named List Filter
Dependencies	`passdb_driver`
See Also	passdb `passdb_name` `passdb_driver`

Creates a new passdb. The filter name refers to the passdb_name setting.

`passdb_default_password_scheme`

Default	`CRYPT` specific passdb have different defaults `passdb_static`: `PLAIN`
Value	string
Changes	Changed: 2.4.3 Changed from `PLAIN` to `CRYPT`.

The scheme that passwords are in the passdb, unless overridden by the passdb entry (typically by prefixing with {SCHEME}).

`passdb_deny`

Default	`no`
Value	boolean

If yes and the user is found from the denied user database the authentication will fail.

`passdb_driver`

Default	[None]
Value	string
See Also	`passdb_name` passdb Authentication Databases

The driver used for this password database. If empty, defaults to passdb_name.

`passdb_fields`

Default	[None]
Value	String List
See Also	passdb: Extra Fields

Passdb fields (and passdb: Extra Fields). The values can contain %variables. All %variables used here reflect the state after the current passdb lookup, and can refer to fields returned by previous passdb lookups. Depending on the passdb driver, it can also refer to variable fields returned by it (e.g. %{ldap:fieldName}).

INFO

The LDAP driver provides additional specific variables, see LDAP authentication for more details.

For example:

passdb ldap {
  fields {
    user = %{ldap:userId}
    proxy = yes
    host = %{ldap:proxyHost}
  }
}

`passdb_fields_import_all`

Default	`yes` For `passdb ldap` the default is `no`.
Value	boolean
See Also	`passdb_fields`

If yes, import all fields returned by the passdb lookup. If no, require passdb_fields to explicitly add wanted fields.

`passdb_ldap_bind`

Default	`no`
Value	boolean

Set yes to use authentication binding for verifying password's validity.

This works by logging into LDAP server using the username and password given by client.

The passdb_ldap_filter is used to find the DN for the user. Note that the passdb_fields are still used, only the password field is ignored in it.

Before doing any search, the binding is switched back to the default DN.

If you use this setting, it's a good idea to use a different ldap_connection_group for userdb. That way one connection is used only for LDAP binds and another connection is used for user lookups. Otherwise the binding is changed to the default DN before each user lookup.

`passdb_ldap_bind_userdn`

Default	[None]
Value	string

If authentication binding is used, you can save one LDAP request per login if users' DN can be specified with a common template. The template can use the standard Settings variables.

Changed: 2.4.3 To avoid unwanted escaping of the output, add | safe filter to the safe variables (i.e. NOT %{user}).

Note that you can't use any %{ldap:*} variables in passdb_fields if you use this setting, because no LDAP fields are looked up.

Examples:

passdb_ldap_bind_userdn = cn=%{user},ou=people,o=org
passdb_ldap_bind_userdn = cn=%{user},%{passdb:domain_dn | safe}

`passdb_ldap_filter`

Default	[None]
Value	string

Filter for passdb lookup.

Variables that can be used (see Settings variables for full list).

Example:

passdb ldap {
  filter = (&(objectClass=posixAccount)(uid=%{user}))
  #...
}

`passdb_master`

Default	`no`
Value	boolean

If yes and the user is found from the Master Users the user is allowed to login as other users.

`passdb_mechanisms_filter`

Default	[None]
Value	Boolean List
Changes	Added: 2.4.0

Skip the passdb if non-empty and the current auth mechanism is not listed here. If the value contains lookup, it matches for non-authenticating passdb lookups (e.g. lmtp/doveadm lookups).

Example:

passdb passwd-file {
  driver = passwd-file
  mechanisms_filter = PLAIN LOGIN
  # ...
}

`passdb_name`

Default	[None]
Value	string
See Also	`passdb` `passdb_driver`

Name of the passdb. The passdb filter name refers to this setting. If the passdb_driver setting is empty, the passdb_name is used as the driver. This allows doing e.g.:

passdb passwd-file {
  passwd_file_path = /etc/dovecot/passwd

`passdb_pam_failure_show_msg`

Default	`no`
Value	boolean

Replace the default Authentication failed reply with PAM's failure.

`passdb_pam_max_requests`

Default	`100`
Value	unsigned integer
See Also	`service_restart_request_count`

Number of requests a auth-worker process handles for passdb pam before it dies. This configures similar behaviour as the service_restart_request_count setting but it limits only the number of pam passdb requests, not all requests to be handled by an auth-worker.

`passdb_pam_service_name`

Default	`dovecot`
Value	string

The PAM service name to be used with the pam passdb.

`passdb_pam_session`

Default	`no`
Value	boolean

Make Dovecot open a PAM session and close it immediately.

`passdb_pam_setcred`

Default	`no`
Value	boolean

Make Dovecot create PAM credentials. The credentials are never deleted, which may cause problems with some PAM plugins.

`passdb_result_failure`

Default	`continue`
Value	string
Allowed Values	`return-okreturnreturn-failcontinuecontinue-okcontinue-fail`
See Also	passdb: Result Values

What to do after the passdb authentication failed. Possible values and their meaning are described fully at passdb: Result Values.

`passdb_result_internalfail`

Default	`continue`
Value	string
Allowed Values	`return-okreturnreturn-failcontinuecontinue-okcontinue-fail`
See Also	passdb: Result Values

What to do after the passdb authentication failed due to an internal error. Possible values and their meaning are described fully at passdb: Result Values. If any of the passdbs had an internal failure and the final passdb also returns continue the authentication will fail with internal error.

`passdb_result_success`

Default	`return-ok`
Value	string
Allowed Values	`return-okreturnreturn-failcontinuecontinue-okcontinue-fail`
See Also	passdb: Result Values

What to do after the passdb authentication succeeded. Possible values and their meaning are described fully at passdb: Result Values.

This is commonly used together with master passdb to specify that even after a successful master user authentication, the authentication should continue to the actual non-master passdb to lookup the user.

`passdb_skip`

Default	`never`
Value	string
Allowed Values	`neverauthenticatedunauthenticated`

Configures when passdbs should be skipped:

Value	Description
`never`	Never skip over this passdb.
`authenticated`	Skip if an earlier passdb already authenticated the user successfully.
`unauthenticated`	Skip if user hasn't yet been successfully authenticated by the previous passdbs.

`passdb_sql_query`

Default	[None]
Value	string
Changes	Changed: 2.4.6 `%{variable}` values are now sent to the database as bind parameters instead of being expanded into the query text. See Variables in Queries for the resulting restrictions.

SQL query to lookup the passdb fields (password and other extra fields).

`passdb_sql_update_query`

Default	[None]
Value	string
Changes	Removed: 2.4.5 Removed together with the `OTP` authentication mechanisms, which was its only user.

SQL query to update the password. Currently used only by the OTP auth mechanism.

`passdb_static_password`

Default	[None]
Value	string
Changes	Added: 2.4.0

The static password to be used for all users authenticating using this passdb.

`passdb_use_worker`

Default	`no` specific passdb have different defaults
Value	boolean

If yes, run the passdb lookup in auth-worker process instead of the main auth process. This setting is only used by some of the passdb drivers.

`passdb_username_filter`

Default	[None]
Value	string

Skip the passdb if non-empty and the username doesn't match the filter. This is mainly used to assign specific passdbs to specific domains. Space or comma-separated list of username filters that can have * or ? wildcards. If any of the filters matches, the filter succeeds. Define negative matches by preceding !. If any of the negative filter matches, the filter won't succeed.

Example:

Filter: *@example.com *@example2.com !user@example.com
Matches:
- any@example.com
- user@example2.com
Won't match:
- user@example.com

`passwd_file_path`

Default	[None]
Value	string

Path to the passwd-file. The path can consists from per-user variables such as s%{user | domain}. If the path starts with static path, then Dovecot ensures that the expanded path does not point outside of this static path. If the path starts with variable, this protection is disabled.

For example if this is set to /etc/dovecot/%{user | domain}/passwd, then using login username such as root@.. won't be allowed to expand into /etc/dovecot../passwd, as that would escape /etc/dovecot.

If you use something like %{env:PREFIX}}/%{user | domain}/passwd as path, it is recommended that PREFIX points to deep enough path, such as /etc/dovecot/domains/, and you do not modify auth_username_chars to avoid including / as allowed character.

`pgsql`

Default	[None]
Value	Named List Filter
See Also	`pgsql_host`

Creates a new PostgreSQL connection. If more than one is specified, the connections are automatically used for load balancing and for failover. The filter name refers to the pgsql_host setting.

`pgsql_connection_limit`

Default	`5`
Value	unsigned integer

Maximum number of parallel connections.

`pgsql_host`

Default	[None]
Value	string
See Also	`pgsql`

Host to connect to. The pgsql setting defaults to this.

`pgsql_parameters`

Default	[None]
Value	String List

List of key/value settings passed to PostgreSQL. See https://www.postgresql.org/docs/current/libpq-connect.html for available parameters.

`pop3_client_workarounds`

Default	[None]
Value	Boolean List

Workarounds for various POP3 client bugs can be enabled here.

The following values are currently supported:

oe-ns-eoh: Because Outlook Express and Netscape Mail expect an end-of-headers line, this option sends one explicitly if none has been sent.
outlook-no-nuls: Because Outlook and Outlook Express hang if messages contain NUL characters, this setting replaces each of them with a 0x80 character.

`pop3_delete_type`

Default	`default`
Value	string
Allowed Values	`defaultflagexpunge`

Action to perform in POP3 when mails are deleted and pop3_deleted_flag is enabled.

`pop3_deleted_flag`

Default	[None]
Value	string
See Also	`pop3_delete_type`

Change POP3 behavior so a user cannot permanently delete messages via POP3.

Instead, the messages are hidden from POP3 sessions by setting an IMAP flag, which Dovecot will filter out in future listings.

To enable this behavior, enter the name of the IMAP keyword to use.

INFO

This keyword will visible on IMAP clients for the message.

Example:

pop3_deleted_flag = $POP3Deleted

`pop3_enable_last`

Default	`no`
Value	boolean

Enable support for the POP3 LAST command.

While this command has been removed from newer POP3 specs, some clients still attempt to use it. Enabling this causes the RSET command to clear all \Seen flags that messages may have.

`pop3_fast_size_lookups`

Default	`no`
Value	boolean

If enabled, use the virtual message size of the message for POP3 replies if available.

POP3 requires message sizes to be listed as if they contain CR+LF line breaks; however, many POP3 servers instead return the sizes with pure line feeds (LFs), for the sake of speed.

If enabled, use the virtual message size if available, before falling back to the incorrect, physical size (used by many POP3 servers) if judging the correct size would have required opening the message to determine.

`pop3_lock_session`

Default	`no`
Value	boolean

If enabled, only one POP3 session may exist for any single user.

`pop3_logout_format`

Default	`top=%{top_count}/%{top_bytes}, retr=%{retr_count}/%{retr_bytes}, del=%{deleted_count}/%{deleted_bytes}, size=%{message_bytes}`
Value	String without variables

The string to display to the client on POP3 logout (informational only).

Variables available (in addition to Mail user variables):

Variable Name	Description
`%{input}`	Bytes read from the client
`%{output}`	Bytes sent to the client
`%{top_count}`	Number of TOP commands run
`%{top_bytes}`	Bytes sent to the client because of TOP commands
`%{retr_count}`	Number of RETR commands run
`%{retr_bytes}`	Bytes sent to the client because of RETR commands
`%{deleted_count}`	Number of deleted messages
`%{deleted_bytes}`	Number of bytes in deleted messages
`%{message_count}`	Number of messages before deletion
`%{message_bytes}`	Mailbox size, in bytes, before deletion
`%{uidl_change}`	The old and the new UIDL hash (which can be useful for identifying unexpected changes in UIDLs)

`pop3_migration_all_mailboxes`

Default	`no`
Value	boolean
Plugin	pop3-migration plugin

By default it's assumed that POP3 contains the same messages as IMAP INBOX. If there are any unexpected mails, the migration fails. If the POP3 server includes other folders' contents in POP3 as well, this setting needs to be enabled. It causes Dovecot to try to match POP3 messages in all the migrated folders, not just INBOX. There is no warning logged if any POP3 UIDLs are missing or if POP3 has messages that aren't found from IMAP.

`pop3_migration_ignore_extra_uidls`

Default	`no`
Value	boolean
Plugin	pop3-migration plugin

If IMAP INBOX has all messages that exist in POP3, but POP3 still has some additional messages, the migration fails. Enable this setting to log it as a warning and continue anyway. This could happen if there's a race condition where a new mail is just delivered and it shows up in POP3 but not in IMAP.

`pop3_migration_ignore_missing_uidls`

Default	`no`
Value	boolean
Plugin	pop3-migration plugin

If POP3 has messages that aren't found from IMAP INBOX, and IMAP INBOX also has messages not found from POP3, the migration fails. Enable this setting to log it as a warning and continue anyway.

`pop3_migration_mailbox`

Default	`no`
Value	string
Plugin	pop3-migration plugin

This setting points to the POP3 INBOX in the configured pop3c namespace. This setting is required for the plugin to be active.

pop3_migration_mailbox = POP3-MIGRATION-NS/INBOX

`pop3_migration_skip_size_check`

Default	`no`
Value	boolean
Plugin	pop3-migration plugin

IMAP and POP3 messages are attempted to be matched by the message sizes by default. This is the most efficient way of matching the messages, since both IMAP and POP3 listings can usually be looked up from indexes/caches. If the IMAP INBOX and POP3 listings don't match exactly, or if two adjacent messages have the same size, the rest of the messages are matched by reading their headers.

If this setting is enabled, the message size check is skipped entirely and only headers are matched. This may be necessary for reliability if it's known that the IMAP and POP3 messages cannot be matched by size anyway.

`pop3_migration_skip_uidl_cache`

Default	`no`
Value	boolean
Plugin	pop3-migration plugin

If imapc is configured with persistent indexes, the POP3 UIDLs are stored into the imapc mailbox's dovecot.index.cache files. Any following incremental migrations use these cached UIDLs if possible. This setting can be used to disable this in case there are any problems with the cache. This setting is unlikely to be ever needed.

`pop3_no_flag_updates`

Default	`no`
Value	boolean

If enabled, do not attempt to mark mail messages as seen or non-recent when a POP3 session is involved.

`pop3_reuse_xuidl`

Default	`no`
Value	boolean

If enabled, and the mail message has an X-UIDL header, use this as the mail's UIDL.

`pop3_save_uidl`

Default	`no`
Value	boolean

Maildir only: If enabled, allow permanent saving of UIDLs sent to POP3 clients so that changes to pop3_uidl_format don't cause future changes to the corresponding UIDLs.

`pop3_uidl_duplicates`

Default	`allow`
Value	string
Allowed Values	`allowrename`

How to handle any duplicate POP3 UIDLs that may exist.

Options:

allow: Show duplicates to clients.
rename: Append a temporary counter (such as -2 or -3) after the UIDL

`pop3_uidl_format`

Default	`%{uid \| hex(8)}%{uidvalidity \| hex(8)}`
Value	String without variables

The POP3 unique mail identifier (UIDL) format to use.

The following variables can be used in combination with the standard variable filters (e.g., %{filename | upper} supplies the filename in uppercase) and with Global variables:

Variable Name	Description
`%{uidvalidity}`	Mailbox's IMAP UIDVALIDITY value
`%{uid}`	IMAP UID associated with the message
`%{md5}`	MD5 sum of the mailbox headers in hex (mbox only)
`%{filename}`	Filename (Maildir only)
`%{guid}`	Dovecot GUID for the message

`pop3c_features`

Default	[None]
Value	Boolean List

List of features, optimizations, and workarounds that can be enabled.

Workarounds:

no-pipelining: Prevents use of the PIPELINING extension even when it is advertised.

`pop3c_host`

Default	[None]
Value	string

The remote POP3 host to connect to.

`pop3c_master_user`

Default	[None]
Value	string
See Also	`pop3c_password` `pop3c_user`

The master username to authenticate as on the remote POP3 host.

To authenticate as a master user but use a separate login user, the following configuration should be employed, where the credentials are represented by masteruser and masteruser-secret:

pop3c_user = %{user}
pop3c_master_user = masteruser
pop3c_password = masteruser-secret

Mail user variables can be used.

`pop3c_password`

Default	[None]
Value	string
See Also	`pop3c_master_user` `pop3c_user`

The authentication password for the remote POP3 server.

If using master users, this setting will be the password of the master user.

`pop3c_port`

Default	`110`
Value	Port Number

The port on the remote POP3 host to connect to.

`pop3c_quick_received_date`

Default	`no`
Value	boolean

If enabled, pop3c doesn't require calling TOP for each message in order to get the metadata.

`pop3c_rawlog_dir`

Default	[None]
Value	directory path
See Also	rawlog
Changes	Changed: 2.4.6 Setting type changed.

Log all POP3 traffic input/output to this directory.

`pop3c_ssl`

Default	`no`
Value	string
Allowed Values	`nopop3sstarttls`

Use TLS to connect to the remote POP3 server.

Value	Description
`no`	No TLS
`pop3s`	Explicitly connect to remote POP3 port using TLS
`starttls`	Use POP3 STARTTLS command to switch to TLS connection

`pop3c_ssl_verify`

Default	`yes`
Value	boolean
See Also	`pop3c_ssl`

Verify remote POP3 TLS certificate?

Verification may be disabled during testing, but should be enabled during production use.

Only used if pop3c_ssl is enabled.

`pop3c_user`

Default	`%{user}`
Value	string
See Also	`pop3c_master_user` `pop3c_password`

The user identity to be used for performing authentication to the source POP3 server.

Mail user variables can be used.

`postmaster_address`

Default	`postmaster@%{user\|domain\|default(hostname)}`
Value	string

The From address from which email rejection messages (bounces) are sent.

As used here, %{user | domain} expands to the domain of the local user. Other Mail user variables can be used as well.

`process_shutdown_filter`

Default	[None]
Value	string

Filter to specify which events shutdown the process after finishing the current connections. This is mainly intended to save memory by preventing long-running imap processes that use a lot of memory (due to libc not freeing all of it to the OS). The syntax of the filter is described in Global Metric Filters.

For example:

process_shutdown_filter = "event=mail_user_session_finished AND rss > 20MB"

`protocols`

Default	[None]
Value	Boolean List

The list of protocols to enable. By default all protocols are disabled.

For example:

# Only IMAP protocol enabled:
protocols = imap

# Enable also LMTP protocol (on top of IMAP):
protocols {
  lmtp = yes
}

`push_notification`

Default	[None]
Value	string
Plugin	push-notification plugin

The configuration value is a named filter for a specified driver, see Push Notifications for their names and their supported options.

`push_notification_driver`

Default	[None]
Value	string
Dependencies	`push_notification`
Plugin	push-notification plugin

The name of the driver. This value determines the available options and the behavior. See Push Notifications for the list of supported drivers and options.

`quota`

Default	[None]
Value	Named List Filter
See Also	Quota Root
Plugin	quota plugin

Create a new quota root. The filter name refers to quota_name setting.

Globally configured quota roots are used only for private namespaces. To use quota for public namespaces, configure it inside the public namespace.

Example:

quota "User quota" {
  storage_size = 1G
}

`quota_clone`

Value	Named Filter
See Also	dictionary
Plugin	quota-clone plugin
Changes	Added: 2.4.0

Named filter for initializing dictionary used to update with quota clone information.

redis_host = 127.0.0.1
redis_port = 6379
quota_clone {
  dict redis {
  }
}

`quota_driver`

Default	`count`
Value	string
See Also	Quota Drivers
Plugin	quota plugin

Quota driver to use. See Quota Drivers.

`quota_enforce`

Default	`yes` `quota_imapc { no }`
Value	boolean
Plugin	quota plugin

If disabled, the quota limit isn't actually enforced. The quota is still tracked and the current quota usage is visible to IMAP GETQUOTA commands.

`quota_exceeded_message`

Default	`Quota exceeded (mailbox for user is full)`
Value	string
Plugin	quota plugin

The message specified here is passed on to a user who goes over quota. There are also other messages, which are currently hard coded:

When exceeding quota_mail_size: Mail size is larger than the maximum size allowed by server configuration
When exceeding quota_mailbox_message_count: Too many messages in the mailbox

`quota_fs_message_limit`

Default	`no`
Value	boolean
Plugin	quota plugin

If yes, use filesystem quota's inode limit as the message count limit. This can be useful with Maildir or sdbox. Used only with Quota Driver: Filesystem.

`quota_fs_mount_path`

Default	[None]
Value	string
Plugin	quota plugin

If specified, enable FS quota for the specified mount path. Only mailboxes existing in this mount path have the quota enabled. Empty value looks up the mountpoint automatically. Used only with Quota Driver: Filesystem.

`quota_fs_type`

Default	`any`
Value	string
Allowed Values	`anyusergroup`
Plugin	quota plugin

Using any attempts to use the user quota first, with a fallback to group quota. Using user or group only attempts to use the user or the group quota, with a fallback to unlimited quota limit. Used only with Quota Driver: Filesystem.

`quota_full_tempfail`

Default	`no`
Value	boolean
See Also	quota plugin

If enabled, return a temporary failure to the sending server if quota is exceeded. This allows the message to potentially be delivered later if the account moves under the quota limit at the time of redelivery.

If disabled, the message is bounced with a permanent error returned to the sending server.

`quota_hidden`

Default	`no`
Value	boolean
Plugin	quota plugin

If yes, hide the quota root from IMAP GETQUOTA commands.

`quota_ignore`

Default	`no`
Value	boolean
Plugin	quota plugin

If yes, don't include this mailbox or namespace in quota calculations.

Example:

namespace inbox {
  mailbox Trash {
    quota_ignore = yes
  }
}
namespace secondary {
  quota_ignore = yes
}

`quota_ignore_unlimited`

Default	`no`
Value	boolean
Plugin	quota plugin

If yes, ignore the quota root entirely if it has no quota limits. This means no tracking of the quota, and not making it visible to IMAP GETQUOTA commands.

`quota_imapc_mailbox_name`

Default	`INBOX`
Value	string
See Also	`quota_imapc_root_name`
Plugin	quota plugin

If non-empty, use GETQUOTAROOT <mailbox> to get the imapc quota root. Used only with Quota Driver: Imapc.

`quota_imapc_root_name`

Default	[None]
Value	string
See Also	`quota_imapc_mailbox_name`
Plugin	quota plugin

If quota_imapc_mailbox_name is empty, use GETQUOTA <name> to get the imapc quota.

Some servers may have an empty quota root name. This is why if this setting and quota_imapc_mailbox_name both have empty values, this setting is used. Used only with Quota Driver: Imapc.

`quota_mail_size`

Default	`unlimited`
Value	size
See Also	Quota: Maximum Saved Mail Size
Plugin	quota plugin

The maximum message size that is allowed to be saved (e.g. by LMTP, IMAP APPEND or doveadm save). If configured, will also be advertized with APPENDLIMIT extensions for IMAP clients, and SIZE extension for LMTP clients.

`quota_mailbox_count`

Default	`unlimited`
Value	unsigned integer
See Also	Quota: Maximum Mailbox Count
Plugin	quota plugin
Changes	Added: 2.4.0

Maximum number of mailboxes that can be created. Each namespace is tracked separately, so e.g. shared mailboxes aren't counted towards the user's own limit.

`quota_mailbox_message_count`

Default	`unlimited`
Value	unsigned integer
Plugin	quota plugin
Changes	Added: 2.4.0

Maximum number of messages that can be created in a single mailbox.

`quota_message_count`

Default	`unlimited`
Value	unsigned integer
See Also	`quota_message_percentage` `quota_storage_size` Quota Root
Plugin	quota plugin

Maximum number of messages for the Quota Root. This value is still multiplied by quota_message_percentage to get the final value (in this mailbox or namespace). This is reported as the MESSAGE limit in IMAP GETQUOTA commands. Using 0 as the value means the same as unlimited.

`quota_message_percentage`

Default	`100`
Value	unsigned integer
See Also	`quota_message_count`
Plugin	quota plugin

Multiplier for the quota_message_count setting (in this mailbox/namespace).

This may be useful to exceed the regular quota limit in some mailboxes, such as allowing clients that move messages with IMAP COPY+EXPUNGE to Trash folder to temporarily exceed the quota.

Example:

quota_message_count = 10000
namespace inbox {
  mailbox Trash {
    # 110% * 10000 = 11000 limit
    quota_message_percentage = 110
  }
}

`quota_name`

Default	[None]
Value	string
See Also	`quota` Quota Root
Plugin	quota plugin

Name of the quota root. The quota filter name refers to this setting.

The quota root name is just an arbitrary string that is sent to IMAP clients, which in turn may show it to the user. The name has no meaning.

`quota_over_status`

Value	Named Filter
See Also	Quota: Overquota Flag
Plugin	quota plugin

Named filter for executing the overquota-flag script. The execute setting is required to be specified inside the filter.

`quota_over_status_current`

Default	[None]
Value	string
See Also	Quota: Overquota Flag
Plugin	quota plugin

An identifier that indicates whether the overquota-flag is active for a user.

This identifier is compared against quota_over_status_mask to determine if the overquota-flag should be set for the user.

Usually, this value will be loaded via userdb.

`quota_over_status_lazy_check`

Default	`no`
Value	boolean
Plugin	quota plugin

If enabled, overquota-flag is checked only when current quota usage is going to already be checked anyway. This prevents any additional storage I/O that would be caused by the overquota-flag check.

`quota_over_status_mask`

Default	[None]
Value	string
See Also	Quota: Overquota Flag
Plugin	quota plugin

The search string to match against quota_over_status_current to determine if the overquota-flag is set for the user.

Wildcards can be used in a generic way, e.g. *yes or *TRUE*.

`quota_status_nouser`

Default	`REJECT Unknown user`
Value	string
See Also	Quota Status Service
Plugin	quota plugin

Quota Status Service: Response when asking quota for a nonexistent users.

`quota_status_overquota`

Default	`554 5.2.2 %{error}`
Value	string
See Also	Quota Status Service
Plugin	quota plugin

Quota Status Service: Response when asking quota for a user that is over the quota. The %{error} variable expands to the more detailed reason, which is generally quota_exceeded_message.

`quota_status_success`

Default	`OK`
Value	string
See Also	Quota Status Service
Plugin	quota plugin

Quota Status Service: Response when asking quota for a user that is under the quota.

`quota_status_toolarge`

Default	`quota_status_overquota`
Value	string
See Also	Quota Status Service
Plugin	quota plugin

Quota Status Service: Response when asking quota for a mail that is larger than user's quota_storage_size or quota_mail_size. Empty value defaults to quota_status_overquota.

`quota_storage_extra`

Default	`0`
Value	size
See Also	`quota_storage_size` `quota_storage_percentage` Quota Root
Plugin	quota plugin

If set, increase the quota_storage_size (for the mailbox/namespace) by this amount. This is an alternative to using quota_storage_percentage, although both can also be used.

This may be useful to exceed the regular quota limit in some mailboxes, such as allowing clients that move messages with IMAP COPY+EXPUNGE to Trash folder to temporarily exceed the quota.

Example:

quota_storage_size = 1G
namespace inbox {
  mailbox Trash {
    # 1G + 100M = 1100M
    quota_storage_extra = 100M
  }
}

`quota_storage_grace`

Default	`10 M`
Value	size
See Also	Quota Root
Plugin	quota plugin

If set, allows message deliveries (LDA, LMTP) to exceed quota once by this amount. After the quota is already over the limit, the grace no longer applies. This prevents a situation where some smaller mails may still become delivered, but larger mail deliveries fail, and the user may not have received any warning about reaching the quota limit.

`quota_storage_percentage`

Default	`100`
Value	unsigned integer
See Also	`quota_storage_size` `quota_storage_extra` Quota Root
Plugin	quota plugin

Multiplier for the quota_storage_size setting (in this mailbox/namespace). This is an alternative to using quota_storage_extra, although both can also be used.

This may be useful to exceed the regular quota limit in some mailboxes, such as allowing clients that move messages with IMAP COPY+EXPUNGE to Trash folder to temporarily exceed the quota.

Example:

quota_storage_size = 1G
namespace inbox {
  mailbox Trash {
    # 110% * 1G = 1100M
    quota_storage_percentage = 110
  }
}

`quota_storage_size`

Default	`unlimited`
Value	size
See Also	`quota_storage_extra` `quota_storage_percentage` `quota_message_count` Quota Root
Plugin	quota plugin

Quota storage size limit for the Quota Root. This value is still multiplied by quota_storage_percentage and then increased by quota_storage_extra to get the final value (in this mailbox or namespace). This is reported as the STORAGE limit in IMAP GETQUOTA commands. Using 0 as the value means the same as unlimited.

`quota_warning`

Default	[None]
Value	Named List Filter
See Also	Quota Warning Scripts
Plugin	quota plugin

Create a new quota warning. The filter name refers to quota_warning_name setting. The execute setting is required to be specified inside the filter.

The order of quota_warning filters in the configuration is important: Only the first warning that matches the rules is executed. This means you must configure the highest limits first.

`quota_warning_name`

Default	[None]
Value	string
See Also	Quota Warning Scripts
Plugin	quota plugin

Name of the quota warning. The quota_warning filter name refers to this setting. This name is only used within the configuration to identify the quota warning - it has no meaning otherwise.

`quota_warning_resource`

Default	`storage`
Value	string
Allowed Values	`storagemessage`
See Also	Quota Warning Scripts
Plugin	quota plugin

Which quota resource the quota warning is tracking.

`quota_warning_threshold`

Default	`over`
Value	string
Allowed Values	`overunder`
See Also	Quota Warning Scripts
Plugin	quota plugin

Should the quota warning be executed when quota grows over the limit, or when it drops under the limit.

`rawlog_dir`

Default	[None]
Value	directory path
See Also	rawlog
Changes	Changed: 2.4.6 Setting type changed. A leading `~/` in the value is now expanded to the user's home directory.

Directory where to create *.in and *.out rawlog files, one per TCP connection. The directory must already exist and be writable by the process. No error is logged if the directory doesn't exist.

Mail user variables can be used.

Example:

protocol imap {
  rawlog_dir = /tmp/rawlog/%{user}
  # if you want to put files into user's homedir, use this, do not use ~
  #rawlog_dir = %{home}/rawlog
}

`recipient_delimiter`

Default	`+`
Value	string

The separator between the :user and :detail address parts.

`redis_db_id`

Default	[None]
Value	unsigned integer

Database number.

`redis_expire`

Default	`infinite`
Value	time

Expiration value for all keys.

`redis_host`

Default	`127.0.0.1`
Value	string

Redis server host.

`redis_key_prefix`

Default	[None]
Value	string

Prefix to add to all keys.

`redis_password`

Default	[None]
Value	string

Redis server password.

`redis_port`

Default	`6379`
Value	Port Number

Redis server port.

`redis_request_timeout`

Default	`30s`
Value	time (milliseconds)

How long to wait for answer before aborting request.

`redis_socket_path`

Default	[None]
Value	string

UNIX socket path to the Redis server. This is preferred over redis_host if both are set.

`rejection_reason`

Default	`Your message to <%{to}> was automatically rejected:%{literal('\r\n')}%{reason}`
Value	String without variables

A human-readable message for the recipients of bounce messages.

The following variables are allowed, including Global variables:

Variable Name	Description
`%{reason}`	Reason for rejection
`%{subject}`	Original subject line
`%{to}`	Recipient address

The variable values are obtained from the mail being delivered or the delivery protocol.

`rejection_subject`

Default	`Rejected: %{subject}`
Value	String without variables
See Also	`rejection_reason`

The Subject: header to use for bounce messages.

See rejection_reason for the list of variables that can be used.

`sendmail_path`

Default	`/usr/sbin/sendmail`
Value	string

The binary to use for sending email.

Used only if submission_host is not set.

`service`

Default	[None]
Value	Named List Filter
See Also	`service_name`

Creates a new service to the list of services. The filter name refers to the service_name setting.

`service_chroot`

Default	[None]
Value	string
See Also	`base_dir`

The processes are chrooted to this directory at startup. Relative to base_dir.

`service_client_limit`

Default	`default_client_limit`
Value	unsigned integer

Maximum number of simultaneous client connections per process. Once this number of connections is received, the next incoming connection will prompt Dovecot to spawn another process.

`service_drop_priv_before_exec`

Default	`no`
Value	boolean

Drop all privileges after forking, but before executing the binary. This is mainly useful for dumping core files on non-Linux OSes, since the processes are no longer in "setuid" mode. This setting can't be used with non-empty chroot.

`service_executable`

Default	[None]
Value	string
See Also	`base_dir`

The binary path to execute and its parameters. If the path doesn't begin with /, it's relative to base_dir.

`service_extra_groups`

Default	[None]
Value	string
See Also	`mail_access_groups`

Secondary UNIX groups that this process belongs to.

WARNING

This may be dangerous to use for the same reason as mail_access_groups.

`service_group`

Default	[None]
Value	string

The primary UNIX group (GID) which runs this process.

`service_idle_kill_interval`

Default	`default_idle_kill_interval`
Value	time

Time interval between killing extra idling processes. During the interval the master process tracks the lowest number of idling processes for the service. Afterwards it sends SIGINT notification to that many idling processes. If the processes are still idling when receiving the signal, they shut down themselves.

Using infinite disables the idle-killing.

`service_name`

Default	[None]
Value	string
See Also	`service`

Name of the service. The service filter name refers to this setting.

`service_process_limit`

Default	`default_process_limit`
Value	unsigned integer

The maximum number of processes that may exist for this service.

Changed: 2.4.5 However, if service_client_limit > 1, when the process reaches service_restart_request_count, the process is no longer counted towards its process limit. Otherwise long-lived connections in the old process could prevent creation of new processes.

`service_process_min_avail`

Default	[None]
Value	unsigned integer
See Also	`service_client_limit` `service_restart_request_count`

Minimum number of processes that always should be available to accept more client connections.

Note that if service_client_limit = 1, this means there are always that many processes that are not doing anything. When a new process launches, one of the idling processes will accept the connection and a new idling process is launched.

For service_restart_request_count = 1 processes this decreases the latency for handling new connections, because there's no need to wait for processes to fork. This is usually not necessary to to be set. Large service_process_min_avail values might be useful in some special cases, like if there are a lot of POP3 users logging in exactly at the same time to check mails.
For service_restart_request_count to a value !=1 and service_client_limit to a value >1 processes it could be set to the number of CPU cores (you can use %{system:cpu_count}) on the system to balance the load among them. This is commonly used with *-login processes.
For service_restart_request_count with a value of !=1 and service_client_limit = 1 processes it is likely not useful to use this, because generally there are already some idling processes waiting to accept new connections. However, it's not harmful either, since service_process_min_avail includes the existing idling processes when counting how many new idling processes are needed.

`service_protocol`

Default	[None]
Value	string
See Also	`protocols`

If non-empty, this service is enabled only when the protocol name is listed in protocols setting.

`service_restart_request_count`

Default	`unlimited`
Value	unsigned integer

Number of client connections to handle until the process kills itself. Use unlimited to keep the process alive. 1 means only a single connection is handled until the process is stopped - this is the most secure choice since there's no way for one connection's state to leak to the next one. For better performance this can be set higher, but ideally not unlimited since more complex services can have small memory leaks and/or memory fragmentation and the process should get restarted eventually. For example 100 or 1000 can be good values.

`service_reuse_port`

Default	`no`
Value	boolean
Changes	Added: 2.4.4

Distribute TCP connections to processes more evenly using the SO_REUSEPORT option on Linux. When enabled, service_process_min_avail must be the same as service_process_limit.

This setting is mainly intended to be enabled for login processes.

When no, all processes listening on the socket try to accept it at the same time. Whichever process is fastest (gets scheduled first by the kernel) gets the connection. This can lead to rather uneven distribution of connections. On the positive side, this behaves more gracefully once the process reaches service_client_limit: it simply doesn't accept new connections, allowing other processes to handle them instead. If all processes are full, the master process rejects new connections.

When yes, a separate listener socker is created for each process at startup. This is why service_process_min_avail must be the same as service_process_limit. Each process gets one of these listener sockets and uses it to accept connections. The kernel assigns incoming connections to these listener sockets based on the connection hash, so the connections should be rather evenly distributed across processes. This also means that if any process has reached service_client_limit, it must start rejecting new connections, even if other processes aren't full. However, because of the more even distribution of connections, it's expected that when one process is full, other processes are nearly full as well.

`service_shutdown_clients_timeout`

Default	`0`
Value	time
See Also	`service_type`
Changes	Added: 2.4.6

How long the processes of the old configuration may keep serving their existing clients after doveadm reload, and how long the processes may keep running after the master process was stopped.

Value	Description
`0`	The default. All the clients are disconnected immediately.
time	The clients are disconnected after this time.
`infinite`	The clients are never disconnected. The processes stop once their last client is gone.

The time is the maximum: when it is up, the processes disconnect all their remaining clients, also the ones that are in the middle of a command, and the login processes abort the logins that are still in progress. A login process that proxies a connection to a backend waits up to two seconds for the connection to become quiet, so that a reply isn't cut in the middle.

Only the processes of service_type = client and service_type = login services and the log process are preserved. The internal services are replaced by the reload, so their old processes are stopped regardless of this setting - otherwise they would pile up with every reload. This means that requests which are in flight to an internal service when its old process is stopped fail, the same way they do when a reload disconnects the clients instead.

The main use case is taking new SSL certificates into use without disconnecting anyone:

service_shutdown_clients_timeout = 4h

The setting can also be set per service, e.g. to keep only the IMAP sessions running:

service_shutdown_clients_timeout = 0
service imap {
  shutdown_clients_timeout = 4h
}
service imap-login {
  shutdown_clients_timeout = 4h
}

Both processes serving a session need the timeout: with TLS the login process keeps proxying the connection also after the login, so the session ends as soon as either of the imap and imap-login processes is killed.

On a proxy there are no local imap processes - the login processes proxy the connections to the backends - so the login service's timeout alone decides how long the existing sessions keep running.

A single reload can override the setting for all the services with doveadm reload --kick-timeout. The override covers also the processes that earlier reloads left running, so --kick-timeout 0 disconnects every preserved client.

WARNING

After the master process has been stopped there is nobody left to escalate to SIGKILL, so a non-zero timeout only means that the processes shut themselves down gracefully at the deadline.

With systemd the default KillMode=control-group kills the preserved processes anyway on systemctl restart. Preserving them across a restart needs KillMode=mixed or KillMode=process.

`service_type`

Default	[None]
Value	string
See Also	`service_process_limit` `service_shutdown_clients_timeout`

Type of this service:

Value	Description
`<empty>`	The default.
`client`	Added: 2.4.6 Used by services whose processes serve externally visible client connections that can't be transparently re-established. A configuration reload preserves these processes, see `service_shutdown_clients_timeout`.
`login`	Used by login services. The login processes have "all processes full" notification fd. It's used by the processes to figure out when no more client connections can be accepted because client and process limits have been reached. The login processes can then kill some of their oldest connections that haven't logged in yet.
`worker`	Used by various worker services. It's normal for worker processes to fill up to `service_process_limit`, and there shouldn't be a warning logged about it.
`startup`	Creates one process at startup.
`log` `config` `anvil`	Treated specially by these specific services.

`service_user`

Default	[None]
Value	string
See Also	`default_login_user` `default_internal_user`

UNIX user (UID) which runs this process. default_login_user should be used for type=login processes and default_internal_user should be used for other processes that don't require root privileges.

`service_vsz_limit`

Default	`default_vsz_limit`
Value	size

Limit the process's address space (both RLIMIT_DATA and RLIMIT_AS if available). When the space is reached, some memory allocations may start failing with "Out of memory", or the kernel may kill the process with signal 9. This setting is mainly intended to prevent memory leaks from eating up all of the memory, but there can be also legitimate reasons why the process reaches this limit. For example a huge mailbox may not be accessed if this limit is too low. Use unlimited to disable this entirely.

`shutdown_clients`

Default	`yes`
Value	boolean
Changes	Removed: 2.4.6 Replaced by `service_shutdown_clients_timeout`, which is the same setting with the time in between also available: `yes` became `0` and `no` became `infinite`.

If enabled, all processes are killed when the master process is shutdown.

Otherwise, existing processes will continue to run. This may be useful to not interrupt earlier sessions, but may not be desirable if restarting Dovecot to apply a security update, for example.

`sieve_editheader_header`

Default	[None]
Value	Named List Filter
See Also	Sieve editheader extension `sieve_editheader_header_name` `sieve_editheader_header_forbid_add` `sieve_editheader_header_forbid_delete`
Plugin	sieve plugin

Configures a new message header, which can be forbidden to be added or deleted. The filter name refers to the sieve_editheader_header_name setting.

`sieve_editheader_header_forbid_add`

Default	`no`
Value	boolean
See Also	Sieve editheader extension `sieve_editheader_header`
Plugin	sieve plugin

Forbid adding the sieve_editheader_header_name to the message header.

Addition of the Subject: header cannot be prohibited, as required by the RFC specification. Therefore, adding this header to this setting has no effect.

`sieve_editheader_header_forbid_delete`

Default	`no`
Value	string
See Also	Sieve editheader extension `sieve_editheader_header`
Plugin	sieve plugin

Forbid deleting the sieve_editheader_header_name from the message header.

Deleting the Received: and Auto-Submitted: fields is always forbidden, while removing the Subject: header cannot be prohibited, as required by the RFC specification. Therefore, using this setting with one of these headers has no effect.

`sieve_editheader_header_name`

Default	[None]
Value	string
See Also	Sieve editheader extension `sieve_editheader_header`
Plugin	sieve plugin

The name of the message header that is forbidden to be added or deleted.

`sieve_editheader_max_header_size`

Default	`2k`
Value	size
See Also	Sieve editheader extension
Plugin	sieve plugin

The maximum size in bytes of a header field value passed to the addheader command.

The minimum value for this setting is 1024 bytes.

`sieve_execute_bin_dir`

Default	[None]
Value	string
Plugin	sieve-extprograms plugin

Points to a directory where the plugin looks for programs (shell scripts) to execute directly for the vnd.dovecot.execute extension.

`sieve_execute_exec_timeout`

Default	`10s`
Value	time
Plugin	sieve-extprograms plugin

Configures the maximum execution time after which the program run by the vnd.dovecot.execute extension is forcibly terminated.

`sieve_execute_input_eol`

Default	`crlf`
Value	string
Allowed Values	`crlflf`
Plugin	sieve-extprograms plugin

Determines the end-of-line character sequence used for the data piped to external programs run by the vnd.dovecot.execute extension. The default is currently "crlf", which represents a sequence of the carriage return (CR) and line feed (LF) characters. This matches the Internet Message Format (RFC 5322) and what Sieve itself uses as a line ending. Set this setting to "lf" to use a single LF character instead.

`sieve_execute_socket_dir`

Default	[None]
Value	string
Plugin	sieve-extprograms plugin

Points to a directory relative to the base_dir where the plugin looks for script service sockets for the vnd.dovecot.execute extension.

`sieve_extensions`

Default	`<see description>`
Value	Boolean List
Plugin	sieve plugin

The Sieve language extensions available to users.

By default, all supported extensions are available, except for deprecated extensions, extensions that add the ability to change messages, extensions that require explicit configuration, or extensions that are still under development.

Some system administrators may want to disable certain Sieve extensions or enable those that are not available by default.

Supported extensions are listed at Sieve extensions.

Example:

# Enable the vacation-seconds extension in addition to all
# extensions enabled by default.
sieve_extensions {
  vacation-seconds = yes
}

`sieve_extlists_list`

Default	[None]
Value	Named List Filter
See Also	Sieve extlists extension
Plugin	sieve plugin

This named list filter creates a new list definition for the ":list" match type in Sieve (extlists extension). The filter name refers to the sieve_extlists_list_name setting. That is the name of the list as it will be accessible from the Sieve. A dict definition that is placed inside the scope of this list filter will serve as the lookup for this extlists list. So, values from Sieve are looked up in the defined dict. This is often used to define an address book or whitelist external to the Sieve script. If no dict is present, the list will function as an empty list.

Example:

sieve_extlists_list :addrbook:default {
  dict proxy {
    name = addressbook
  }
}

`sieve_extlists_list_max_lookup_size`

Default	`1k`
Value	size
See Also	Sieve extlists extension
Plugin	sieve plugin

The maximum size of a value looked up from this Sieve extlists list. If the value is too large, the lookup will be skipped and will yield no result. Note that individual lists may have different limits, meaning that lookups in other lists may still succeed.

`sieve_extlists_list_name`

Default	[None]
Value	string
See Also	Sieve extlists extension
Plugin	sieve plugin

The name of the list as it will be accessible through the Sieve ":list" match type (extlists extension). According to the standard, this name must be a valid URI. This implementation further limits that to a valid URN or TAG URI. Note that the standard URN and TAG equality rules dictate that at least parts of these URIs are case-sensitive, so it is best to consider the configured name case-sensitive entirely.

The sieve_extlists_list filter refers to this setting.

`sieve_filter_bin_dir`

Default	[None]
Value	string
Plugin	sieve-extprograms plugin

Points to a directory where the plugin looks for programs (shell scripts) to execute directly and filter messages through for the vnd.dovecot.filter extension.

`sieve_filter_exec_timeout`

Default	`10s`
Value	time
Plugin	sieve-extprograms plugin

Configures the maximum execution time after which the program run by the vnd.dovecot.filter extension is forcibly terminated.

`sieve_filter_input_eol`

Default	`crlf`
Value	string
Allowed Values	`crlflf`
Plugin	sieve-extprograms plugin

Determines the end-of-line character sequence used for the data piped to external programs run by the vnd.dovecot.filter extension. The default is currently "crlf", which represents a sequence of the carriage return (CR) and line feed (LF) characters. This matches the Internet Message Format (RFC 5322) and what Sieve itself uses as a line ending. Set this setting to "lf" to use a single LF character instead.

`sieve_filter_socket_dir`

Default	[None]
Value	string
Plugin	sieve-extprograms plugin

Points to a directory relative to the base_dir where the plugin looks for script service sockets for the vnd.dovecot.filter extension.

`sieve_global_extensions`

Default	`sieve_extensions`
Value	Boolean List
Plugin	sieve plugin

Which Sieve language extensions are only available in global scripts.

This can be used to restrict the use of certain Sieve extensions to administrator control, for instance when these extensions can cause security concerns.

This setting has higher precedence than sieve_extensions, meaning that the extensions enabled with this setting are never available to the user's personal script no matter what is specified for the sieve_extensions setting.

The syntax of this setting is identical to sieve_extensions, with the difference that extensions are enabled or disabled for exclusive use in global scripts.

Currently, no extensions are marked as such by default.

`sieve_implicit_extensions`

Default	[None]
Value	string
Plugin	sieve plugin

WARNING

Do not use this setting unless you really need to!

The Sieve language extensions implicitly available to users.

The extensions listed in this setting do not need to be enabled explicitly using the Sieve "require" command.

This behavior directly violates the Sieve standard, but can be necessary for compatibility with some existing implementations of Sieve (notably jSieve).

The syntax and semantics of this setting are otherwise identical to sieve_extensions.

`sieve_max_actions`

Default	`32`
Value	unsigned integer
See Also	`sieve_max_redirects` `sieve_notify_max_notifications`
Plugin	sieve plugin

The maximum number of actions that can be performed during a single script execution.

If set to 0, no limit on the total number of actions is enforced.

This is the total across all action classes. Per-class limits such as sieve_max_redirects and sieve_notify_max_notifications apply on top: the effective per-class limit is min(per_class_setting, sieve_max_actions). When the total cap is hit first, execution aborts with "total number of actions exceeds policy limit".

`sieve_max_cpu_time`

Default	`30s`
Value	time
See Also	`sieve_resource_usage_timeout`
Plugin	sieve plugin
Changes	Changed: 2.4.5 Changed from `0` (unlimited) to `30s`. Previously, `30s` was the default only for the `sieve_env_location_ms` (IMAP) filter; it now applies globally including MDA execution.

The maximum amount of CPU time that a Sieve script is allowed to use while executing. If the execution exceeds this resource limit, the script ends with an error, causing the implicit "keep" action to be executed.

This limit is not only enforced per single script execution; CPU time used across executions within sieve_resource_usage_timeout is summed and compared against this limit as well.

See sieve_resource_usage_timeout for more details on how the limits work.

Changed: 2.4.5 Execution is refused while the cumulative usage is over the limit, and resumes automatically once the recorded usage falls below the limit. Previously, exceeding the cumulative limit blocked the script permanently until it was recompiled (e.g. via sievec) or re-uploaded.

`sieve_max_redirects`

Default	`4`
Value	unsigned integer
See Also	`sieve_max_actions`
Plugin	sieve plugin

The maximum number of redirect actions that can be performed during a single script execution.

0 means redirect is prohibited.

The effective per-script limit on redirect actions is min(sieve_max_redirects, sieve_max_actions): when the total number of actions in a script reaches sieve_max_actions (default 32), execution aborts with "total number of actions exceeds policy limit" before this per-class limit is reached. To allow more than sieve_max_actions redirect actions, raise that setting as well.

`sieve_notify_mailto_envelope_from`

Default	[None]
Value	string
See Also	`sieve_redirect_envelope_from` Sieve notifications extensions
Plugin	sieve plugin

Defines the source of the notification sender address for e-mail notifications.

`sieve_pipe_bin_dir`

Default	[None]
Value	string
Plugin	sieve-extprograms plugin

Points to a directory where the plugin looks for programs (shell scripts) to execute directly and pipe messages to for the vnd.dovecot.pipe extension.

`sieve_pipe_exec_timeout`

Default	`10s`
Value	time
Plugin	sieve-extprograms plugin

Configures the maximum execution time after which the program run by the vnd.dovecot.pipe extension is forcibly terminated.

`sieve_pipe_input_eol`

Default	`crlf`
Value	string
Allowed Values	`crlflf`
Plugin	sieve-extprograms plugin

Determines the end-of-line character sequence used for the data piped to external programs run by the vnd.dovecot.pipe extension. The default is currently "crlf", which represents a sequence of the carriage return (CR) and line feed (LF) characters. This matches the Internet Message Format (RFC 5322) and what Sieve itself uses as a line ending. Set this setting to "lf" to use a single LF character instead.

`sieve_pipe_socket_dir`

Default	[None]
Value	string
Plugin	sieve-extprograms plugin

Points to a directory relative to the base_dir where the plugin looks for script service sockets for the vnd.dovecot.pipe extension.

`sieve_plugins`

Default	[None]
Value	Boolean List
Plugin	sieve plugin

The Pigeonhole Sieve interpreter can have plugins of its own.

Using this setting, the used plugins can be specified.

Check Sieve plugins for available plugins.

`sieve_quota_script_count`

Default	`unlimited`
Value	unsigned integer
Plugin	sieve plugin

The maximum number of personal Sieve scripts a single user can have.

`sieve_quota_storage_size`

Default	`unlimited`
Value	size
Plugin	sieve plugin

The maximum amount of disk storage a single user's scripts may occupy.

`sieve_redirect_envelope_from`

Default	`sender`
Value	string
Plugin	sieve plugin

Specifies what envelope sender address is used for redirected messages.

Normally, the Sieve redirect command copies the sender address for the redirected message from the processed message So, the redirected message appears to originate from the original sender.

The following options are supported for this setting:

Option	Description
`sender`	The sender address is used
`recipient`	The final recipient address is used
`orig_recipient`	The original recipient is used
`user_email`	The user's primary address is used. This is configured with the `sieve_user_email` setting. If that setting is not configured, `user_email` is equal to `sender`.
`postmaster`	The `postmaster_address` configured for LDA/LMTP.
`<user@domain>`	Redirected messages are always sent from `user@domain`. The angle brackets are mandatory. The null `<>` address is also supported.

When the envelope sender of the processed message is the null address <>, the envelope sender of the redirected message is also always <>, irrespective of what is configured for this setting.

`sieve_resource_usage_timeout`

Default	`1h`
Value	time
See Also	`sieve_max_cpu_time`
Plugin	sieve plugin

To prevent abuse, the Sieve interpreter records CPU time used by Sieve script executions in a per-user file sieve-rusage at the root of the user's INBOX namespace. Only significant executions are recorded; currently this means CPU system + user time exceeding 1.5 seconds for one execution. Such high resource usage is summed over time and once the cumulative total exceeds sieve_max_cpu_time, further script execution is refused for that user, even if an individual execution exceeded no limits.

If the last time high resource usage was recorded is older than sieve_resource_usage_timeout, the recorded value is treated as zero. This means a user is only blocked when the limits are cumulatively exceeded within this timeout, and is automatically re-enabled once the timeout elapses with no further significant CPU consumption. With the default configuration a user is blocked only when the total CPU time of Sieve executions that lasted more than 1.5 seconds exceeds 30 seconds within the last hour, and execution resumes one hour after the last significant run.

Changed: 2.4.5 Tracking is per user, not per script: re-uploading a script under a different name, renaming or deleting and recreating it does not reset the recorded usage. An administrator can force an immediate reset by removing the sieve-rusage file from the user's INBOX namespace root.

`sieve_script`

Default	[None]
Value	Named List Filter
See Also	Script storage
Plugin	sieve plugin

Creates a new Sieve script storage to the list of script storages. The filter name refers to the sieve_script_storage setting.

Example:

sieve_script personal {
  [...]
}

`sieve_script_active_path`

Default	`~/.dovecot.sieve`
Value	string
See Also	File storage driver
Plugin	sieve plugin

When ManageSieve server is used, one script in the storage can be active; i.e., evaluated at delivery.

This setting only applies when sieve_script_driver = file. For that storage driver, the active script in the storage directory is pointed to by a symbolic link.

This setting configures where this symbolic link is located. If the sieve_script_path setting points to a regular file, this setting has no effect (and ManageSieve cannot be used).

`sieve_script_bin_path`

Default	`personal`
Value	string
See Also	Script storage
Plugin	sieve plugin

Points to the directory where the compiled binaries for this script location are stored. This directory is created automatically if possible.

If this setting is not configured, the behavior depends on the storage driver. For the file storage driver, the binaries are for example stored in the same directory as the corresponding sieve scripts.

Don't specify the same directory for multiple script storages (e.g. with different types), as this will result in undefined behavior. For one, the same script name could point to different scripts for different storages, leading to a conflict, because the storages will try to use the same binary file. Multiple mail users can share a single script directory if the associated script storage configuration is identical between users and all users share the same system credentials (uid, gid). All users will then use the same scripts for that storage type.

`sieve_script_cause`

Default	`delivery`
Value	Boolean List
See Also	Script storage
Plugin	sieve plugin

The causes for executing Sieve scripts from this storage. This is currently only relevant for the IMAPSieve plugin. For standard Sieve execution at message delivery the cause is "delivery". Other causes can be append, copy and flag.

`sieve_script_driver`

Default	`file`
Value	string
See Also	Script storage
Plugin	sieve plugin

The Sieve script storage driver to use. See Script storage drivers.

`sieve_script_ldap_filter`

Default	[None]
Value	string
See Also	LDAP storage driver
Plugin	sieve plugin

The LDAP search filter that is used to find the entry containing the Sieve script.

These variables can be used:

Variable	Description
`%{user}`	username
`%{user \| username}`	user part in user@domain, same as `%{user}` if there's no domain
`%{user \| domain}`	domain part in user@domain, empty if user there's no domain
`%{home}`	user's home directory
`%{name}`	name of the Sieve script Added: 2.4.6

Changed: 2.4.6 The variables are LDAP-escaped, so that they cannot break out of the filter. To avoid the escaping, add the | safe filter to the variable.

`sieve_script_ldap_modified_attribute`

Default	[None]
Value	string
See Also	LDAP storage driver
Plugin	sieve plugin

The name of the attribute used to detect modifications to the LDAP entry.

`sieve_script_ldap_script_attribute`

Default	[None]
Value	string
See Also	LDAP storage driver
Plugin	sieve plugin

The name of the attribute containing the Sieve script.

`sieve_script_name`

Default	`personal`
Value	string
See Also	Script storage
Plugin	sieve plugin

The (default) name of a Sieve script retrieved from this storage. If the name of the Sieve script cannot be derived somehow from the storage (e.g. from a file name) and the storage for a single script is specified, this option is required (e.g. for dict locations that must point to a particular script).

If the name of the script is derived from the storage, the value of the sieve_script_name setting overrides that name. If the Sieve interpreter explicitly queries for a specific name (e.g. to let the Sieve Sieve include extension retrieve a script from the global script storage), this setting has no effect.

For the Sieve script storage with type default, the name is required to make the default script visible in ManageSieve. See 'Sieve visible default script'

`sieve_script_path`

Default	`~/sieve`
Value	string
See Also	File storage driver
Plugin	sieve plugin

A file system path pointing to a Sieve script file or a directory containing one or more Sieve script files with names structured as <script-name>.sieve. This setting only applies when sieve_script_driver = file

`sieve_script_precedence`

Default	`infinite`
Value	unsigned integer
See Also	Script storage
Plugin	sieve plugin

The precedence of this Sieve storage in the configuration. Normally, script storages with matching type and cause are accessed in the order these are specified in the configuration. This setting can be used to configure an explicit order. Storages will be accessed with lower precedence first.

`sieve_script_storage`

Default	[None]
Value	string
See Also	Script storage
Plugin	sieve plugin

The identifier of the Sieve script storage. This is used only in configurations and by command line tools - it's not visible to the user. The sieve_script filter refers to this setting.

`sieve_script_type`

Default	`personal`
Value	string
See Also	Script storage types
Plugin	sieve plugin

The type of the configured Sieve script storage. See Script storage types.

`sieve_spamtest_score_max_header`

Default	[None]
Value	string
See Also	Sieve spamtest extension
Plugin	sieve plugin

Value format: <header-field> [ ":" <regexp> ]

Some spam scanners include the maximum score value in one of their status headers. Using this setting, this maximum can be extracted from the message itself instead of specifying the maximum manually using the setting sieve_spamtest_score_max_value.

The syntax is identical to the sieve_spamtest_status_header setting. This setting cannot be used together with sieve_spamtest_score_max_value.

`sieve_spamtest_score_max_value`

Default	[None]
Value	string
See Also	Sieve spamtest extension
Plugin	sieve plugin

This statically specifies the maximum value a numeric spam score can have. This setting cannot be used together with sieve_spamtest_score_max_header. This setting can specify a fractional score with a decimal point.

`sieve_spamtest_status_header`

Default	[None]
Value	string
See Also	Sieve spamtest extension
Plugin	sieve plugin

Value format: <header-field> [ ":" <regexp> ]

This specifies the header field that contains the result information of the spam scanner and it may express the syntax of the content of the header.

If no matching header is found in the message, the spamtest command will match against 0.

This is a structured setting. The first part specifies the header field name. Optionally, a POSIX regular expression follows the header field name, separated by a colon. Any white space directly following the colon is not part of the regular expression. If the regular expression is omitted, any header content is accepted and the full header value is used. When a regular expression is used, it must specify one match value (inside brackets) that yields the desired spam scanner result.

If the header does not match the regular expression or if no value match is found, the spamtest test will match against 0 during Sieve script execution.

`sieve_spamtest_status_type`

Default	[None]
Value	string
Allowed Values	`scorestrlentext`
See Also	Sieve spamtest extension
Plugin	sieve plugin

This specifies the type of status result that the spam/virus scanner produces.

This can either be a numeric score (score), a string of identical characters (strlen), e.g. '*******', or a textual description (text), e.g. 'Spam' or 'Not Spam' (see sieve_spamtest_text_value).

`sieve_spamtest_text_value`

Default	[None]
Value	String List
See Also	Sieve spamtest extension
Plugin	sieve plugin

When the sieve_spamtest_status_type setting is set to text, this setting specifies what values the spamtest test will match against to obtain the score value. For each recognized numeric score value this string list setting yields the text to match against. Score values between 0 and 10 are recognized.

Example:

sieve_spamtest_status_header = X-Spam-Verdict
sieve_spamtest_status_type = text
sieve_spamtest_text_value {
  1 = Not Spam
  10 = Spam
}

`sieve_trace_addresses`

Default	`no`
Value	boolean
See Also	Sieve trace debugging
Plugin	sieve plugin

Enables showing byte code addresses in the trace output, rather than only the source line numbers.

`sieve_trace_debug`

Default	`no`
Value	boolean
See Also	Sieve trace debugging
Plugin	sieve plugin

Enables highly verbose debugging messages that are usually only useful for developers.

`sieve_trace_dir`

Default	[None]
Value	string
See Also	Sieve trace debugging
Plugin	sieve plugin

The directory where trace files are written.

Trace debugging is disabled if this setting is not configured or if the directory does not exist.

If the path is relative or it starts with ~/ it is interpreted relative to the current user's home directory.

`sieve_trace_level`

Default	[None]
Value	string
See Also	Sieve trace debugging
Plugin	sieve plugin

The verbosity level of the trace messages. Trace debugging is disabled if this setting is not configured. Options are:

Option	Description
`actions`	Only print executed action commands, like keep, fileinto, reject, and redirect.
`commands`	Print any executed command, excluding test commands.
`tests`	Print all executed commands and performed tests.
`matching`	Print all executed commands, performed tests and the values matched in those tests.

`sieve_user_email`

Default	[None]
Value	string
Plugin	sieve plugin

The primary e-mail address for the user.

This is used as a default when no other appropriate address is available for sending messages.

If this setting is not configured, either the postmaster or null <> address is used as a sender, depending on the action involved.

This setting is important when there is no message envelope to extract addresses from, such as when the script is executed in IMAP.

`sieve_user_log_path`

Default	[None]
Value	string
Plugin	sieve plugin

The path to the file where the user log file is written.

A default location is used if this setting is not explicitly configured:

If the main user's personal Sieve script storage (as configured with sieve_script uses the File storage driver, the logfile is set to <filename>.log by default.
If the script is not stored as a file, the default user log file is ~/.dovecot.sieve.log.

`sieve_vacation_check_recipient`

Default	`yes`
Value	boolean
See Also	Sieve vacation extension
Plugin	sieve plugin

This setting determines whether the checks for implicit delivery are performed. If this is skipped, this means that the vacation command does not verify that the message is explicitly addressed at the recipient.

Use this option with caution. Specifying no will violate the Sieve standards and can cause vacation replies to be sent for messages not directly addressed at the recipient.

`sieve_vacation_default_period`

Default	`7d`
Value	time
See Also	Sieve vacation extension
Plugin	sieve plugin

Specifies the default period that is used when no :days or :seconds tag is specified.

The configured value must lie between sieve_vacation_min_period and sieve_vacation_max_period.

`sieve_vacation_max_period`

Default	`60d`
Value	time
See Also	Sieve vacation extension
Plugin	sieve plugin

Specifies the maximum period that can be specified for the :days tag of the vacation command.

The configured value must be larger than sieve_vacation_min_period.

A value of 0 has a special meaning: it indicates that there is no upper limit.

`sieve_vacation_min_period`

Default	`1d`
Value	time
See Also	Sieve vacation extension
Plugin	sieve plugin

Specifies the minimum period that can be specified for the :days and :seconds tags of the vacation command.

A minimum of 0 indicates that users are allowed to make the Sieve interpreter send a vacation response message for every incoming message that meets the other reply criteria (refer to RFC 5230). A value of zero is not recommended.

`sieve_vacation_send_from_recipient`

Default	`no`
Value	boolean
See Also	Sieve vacation extension
Plugin	sieve plugin

This setting determines whether vacation messages are sent with the SMTP MAIL FROM envelope address set to the recipient address of the Sieve script owner.

Normally this is set to <>, which is the default as recommended in the specification. This is meant to prevent mail loops. However, there are situations for which a valid sender address is required and this setting can be used to accommodate for those.

`sieve_vacation_use_original_recipient`

Default	`no`
Value	boolean
See Also	Sieve vacation extension
Plugin	sieve plugin

This specifies whether the original envelope recipient should be used in the check for implicit delivery.

The vacation command checks headers of the incoming message, such as To: and Cc: for the address of the recipient, to verify that the message is explicitly addressed at the recipient. If the recipient address is not found, the vacation action will not trigger a response to prevent sending a reply when it is not appropriate.

Normally only the final recipient address is used in this check. This setting allows including the original recipient specified in the SMTP session if available.

This is useful to handle mail accounts with aliases. Use this option with caution: if you are using aliases that point to more than a single account, as senders can get multiple vacation responses for a single message.

Use the LDA -a option or the LMTP/LDA lda_original_recipient_header setting to make the original SMTP recipient available to Sieve.

`sieve_virustest_score_max_header`

Default	[None]
Value	string
See Also	Sieve virustest extension
Plugin	sieve plugin

Value Format: <header-field> [ ":" <regexp> ]

The syntax is identical to sieve_virustest_status_header. This setting cannot be used together with sieve_virustest_score_max_value.

`sieve_virustest_score_max_value`

Default	[None]
Value	string
See Also	Sieve virustest extension
Plugin	sieve plugin

This statically specifies the maximum value a numeric spam score can have. This setting cannot be used together with sieve_virustest_score_max_header. This setting can specify a fractional score with a decimal point.

`sieve_virustest_status_header`

Default	[None]
Value	string
See Also	Sieve virustest extension
Plugin	sieve plugin

Value Format: <header-field> [ ":" <regexp> ]

This specifies the header field that contains the result information of the spam scanner and it may express the syntax of the content of the header.

If no matching header is found in the message, the spamtest command will match against 0.

If the header does not match the regular expression or if no value match is found, the spamtest test will match against 0 during Sieve script execution.

`sieve_virustest_status_type`

Default	[None]
Value	string
Allowed Values	`scorestrlentext`
See Also	Sieve virustest extension
Plugin	sieve plugin

This specifies the type of status result that the spam/virus scanner produces.

`sieve_virustest_text_value`

Default	[None]
Value	String List
See Also	Sieve virustest extension
Plugin	sieve plugin

When the sieve_virustest_status_type setting is set to text, this setting specifies what values the spamtest test will match against to obtain the score value. For each recognized numeric score value this string list setting yields the text to match against. Score values between 0 and 10 are recognized.

Example:

sieve_virustest_status_header = X-VirusCheck
sieve_virustest_status_type = text
sieve_virustest_text_value {
  1 = Clean
  2 = Presumed Clean
  3 = Not sure
  4 = Almost Certain
  5 = Definitely
}

`sql_driver`

Default	[None]
Value	string

SQL driver to use for any SQL database accesses.

`sqlite_journal_mode`

Default	`wal`
Value	string
Allowed Values	`deletewal`

Allows using write-ahead logging mode for database.

`sqlite_path`

Default	[None]
Value	string

Path to the sqlite database.

`sqlite_readonly`

Default	`no`
Value	boolean

Specifies that this database is read-only and should not be attempted to be created or written to.

`sqlite_synchronous`

Default	`default`
Value	string
Allowed Values	`defaultoffnormalfullextra`
Changes	Added: 2.4.3

Sets the synchronization mode for SQlite database. See https://sqlite.org/pragma.html#pragma_synchronous for full explanation of values. This has no effect if database is opened in read-only mode. Setting special value default elides pragma call.

`ssl`

Default	`yes`
Value	string
Allowed Values	`yesnorequired`
See Also	SSL configuration `inet_listener_ssl`

The level of SSL support. This setting affects both the implicit SSL ports and the STARTTLS commands.

Options:

no: SSL/TLS is completely disabled.
yes: SSL/TLS is enabled, but not necessarily required for clients.
required: SSL/TLS (or otherwise secure connection) is required for all imap, pop3, managesieve and submission protocol client connections. This differs from auth_allow_cleartext in that even non-cleartext authentication mechanisms aren't allowed without SSL/TLS. See secured connections for details which connections are considered secured.

The value of this setting affects the secured state of connections. See secured connections.

Note: Do not confuse this with the inet_listener_ssl setting, which gets used inside inet_listener { ssl }.

`ssl_cipher_list`

Default	`ALL:!kRSA:!SRP:!kDHd:!DSS:!aNULL:!eNULL:!EXPORT:!DES:!3DES:!MD5:!PSK:!RC4:!ADH:!LOW@STRENGTH (for ssl_server, empty for ssl_client)`
Value	string
See Also	`ssl` `ssl_cipher_suites` `ssl_min_protocol` SSL configuration

The list of SSL ciphers to use for TLSv1.2 and below connections, in order of preference. Use ssl_cipher_suites for TLSv1.3 connections.

You do not need to edit this setting in order to disable specific SSL protocols; that is best done with ssl_min_protocol instead.

This setting is used for both incoming and outgoing SSL connections.

`ssl_cipher_suites`

Default	`<OpenSSL version specific>`
Value	string
See Also	`ssl` `ssl_cipher_list` SSL configuration

The list of SSL cipher suites to use for TLSv1.3 connections, in order of preference. Use ssl_cipher_list for TLSv1.2 and below connections.

This setting is used for both incoming and outgoing SSL connections.

See: https://wiki.openssl.org/index.php/TLS1.3#Ciphersuites

`ssl_client`

Value	Named Filter
See Also	`ssl` `ssl_server` SSL configuration

Named filter, which can be used for specifying SSL client settings.

`ssl_client_ca_dir`

Default	[None]
Value	string
See Also	`ssl` `ssl_client_ca_file` SSL configuration

The directory where trusted SSL CA certificates can be found. For example /etc/ssl/certs. These certificates are used only for outgoing SSL connections (e.g. with the imapc driver).

For extra security you might want to point to a directory containing certificates only for the CAs that are actually needed for the server operation instead of all the root CAs.

If both ssl_client_ca_dir and ssl_client_ca_file are empty, the system CA certificates are used.

`ssl_client_ca_file`

Default	[None]
Value	File
See Also	`ssl` `ssl_client_ca_dir` SSL configuration

File containing the trusted SSL CA certificates. For example /etc/ssl/certs/ca-bundle.crt.

These certificates are used only for outgoing SSL connections (e.g. with the imapc driver).

Note that this setting isn't recommended to be used with large CA bundles, because all the certificates are read into memory. This leads to excessive memory usage, because it gets multiplied by the number of imap processes. It's better to either use ssl_client_ca_dir setting or use a CA bundle that only contains the CAs that are actually necessary for the server operation.

If both ssl_client_ca_dir and ssl_client_ca_file are empty, the system CA certificates are used.

`ssl_client_cert_file`

Default	[None]
Value	File
See Also	`ssl` `ssl_client_key_file` SSL configuration

Public SSL certificate used for outgoing SSL connections. This is generally needed only when the server authenticates the client using the certificate.

ssl_client_key_file is also needed for the private certificate.

Example:

ssl_client_cert_file = /etc/dovecot/dovecot-client.crt
ssl_client_key_file = /etc/dovecot/dovecot-client.key

`ssl_client_key_file`

Default	[None]
Value	File
See Also	`ssl` `ssl_client_cert_file` SSL configuration

Private key for ssl_client_cert_file. If it is password protected, set the password with ssl_client_key_password.

Example:

ssl_client_cert_file = /etc/dovecot/dovecot-client.crt
ssl_client_key_file = /etc/dovecot/dovecot-client.key

`ssl_client_key_password`

Default	[None]
Value	string
See Also	`ssl` `ssl_client_key_file` SSL configuration

Password for the ssl_client_key_file.

`ssl_client_require_valid_cert`

Default	`yes`
Value	boolean
See Also	`ssl` SSL configuration

Require a valid certificate when connecting to external SSL services?

`ssl_crypto_device`

Default	[None]
Value	string
See Also	`ssl` SSL configuration

Available Values: <Obtain by running openssl engine command>

Which SSL crypto device to use.

`ssl_curve_list`

Default	`<defaults from the SSL library>`
Value	string
See Also	`ssl` SSL configuration

Colon separated list of elliptic curves to use, in order of preference. An empty value uses the defaults from the SSL library.

This setting is used for both incoming and outgoing SSL connections.

Example:

ssl_curve_list = P-521:P-384:P-256

`ssl_min_protocol`

Default	`TLSv1.2`
Value	string
See Also	`ssl` `ssl_cipher_list` SSL configuration

The minimum SSL protocol version Dovecot accepts. It cannot be empty.

This setting is used for both incoming and outgoing SSL connections.

Supported values are:

ANY: WARNING

This value is meant for tests only. It should not be used in any deployment of any value/relevance.
TLSv1: Support TLSv1+. (TLSv1 deprecated: RFC 8996)
TLSv1.1: Support TLSv1.1+. (TLSv1.1 deprecated: RFC 8996)
TLSv1.2: Support TLSv1.2+.
TLSv1.3: Support TLSv1.3+.
LATEST: Support only the latest version available.

`ssl_options`

Default	[None]
Value	string
Allowed Values	`compressionno_ticket`
See Also	`ssl` SSL configuration

Additional options for SSL.

This setting is used for both incoming and outgoing SSL connections.

Currently supported options are:

compression: Enable compression.
no_ticket: Disable SSL session tickets.

`ssl_peer_certificate_fingerprint_hash`

Default	[None]
Value	string
See Also	`ssl` SSL configuration passdb: check_client_fp Extra field

An OpenSSL digest algorithm name to use to hash peer certificate names. Setting this value is required for ssl_client_cert_fp and ssl_client_cert_pubkey_fp availability in login_log_format_elements and also in authentication variables. Weak algorithms are explicitly disallowed, such as MD5.

`ssl_server`

Value	Named Filter
See Also	`ssl` `ssl_client` SSL configuration

Named filter, which can be used for specifying SSL server settings.

`ssl_server_alt_cert_file`

Default	[None]
Value	File
See Also	`ssl` SSL configuration

Alternative SSL certificate that will be used if the algorithm differs from the primary certificate.

This is useful when migrating to e.g. an ECDSA certificate.

Example:

ssl_server_alt_cert_file = /path/to/alternative/cert.pem

`ssl_server_alt_key_file`

Default	[None]
Value	File
See Also	`ssl` `ssl_server_alt_cert_file` SSL configuration

Private key for ssl_server_alt_cert_file.

Example:

ssl_server_alt_key_file = /path/to/alternative/key.pem
ssl_server_alt_cert_file = /path/to/alternative/cert.pem

`ssl_server_ca_file`

Default	[None]
Value	File
See Also	`ssl` `ssl_client_require_valid_cert` `ssl_server_request_client_cert`

List of SSL CA certificates that are used to validate whether SSL certificates presented by incoming imap/pop3/etc. client connections are valid.

Example:

ssl_server_ca_file = /etc/dovecot/ca.crt
ssl_server_request_client_cert = yes
auth_ssl_require_client_cert = yes

`ssl_server_cert_file`

Default	[None]
Value	File
See Also	`ssl` `ssl_server_key_file` SSL configuration

Path to the PEM-encoded X.509 SSL/TLS certificate presented for incoming imap/pop3/etc. client connections.

The ssl_server_key_file is also needed for the private certificate.

Example:

ssl_server_cert_file = /etc/ssl/private/dovecot.crt
ssl_server_key_file = /etc/ssl/private/dovecot.key

`ssl_server_cert_username_field`

Default	`commonName`
Value	string
See Also	`ssl` SSL configuration

Field name in the SSL client certificate that is used for auth_ssl_username_from_cert.

The most common choices are commonName and x500UniqueIdentifier.

Note: auth_ssl_username_from_cert MUST be enabled.

`ssl_server_dh_file`

Default	[None]
Value	File
See Also	`ssl` SSL configuration

Path to the Diffie-Hellman parameters file. This setting isn't needed if using only ECDSA certificates.

You can generate a new parameters file by, for example, running openssl dhparam -out dh.pem 4096 on a machine with sufficient entropy (this may take some time).

Example:

ssl_server_dh_file = /path/to/dh.pem

`ssl_server_key_file`

Default	[None]
Value	File
See Also	`ssl` `ssl_server_cert_file` `ssl_server_key_password` SSL configuration

Path to the PEM-encoded X.509 SSL/TLS private key for ssl_server_cert_file.

Example:

ssl_server_cert_file = /etc/ssl/private/dovecot.crt
ssl_server_key_file = /etc/ssl/private/dovecot.key

`ssl_server_key_password`

Default	[None]
Value	string
See Also	`ssl` `ssl_server_key_file` SSL configuration

The password to use if ssl_server_key_file is password-protected.

Since this file is often world-readable, you may wish to specify the path to a file containing the password, rather than the password itself, by using the format ssl_server_key_password = <path here. The path should be to a root-owned file with mode 0600.

Alternatively, you can supply the password via the -p parameter at startup.

`ssl_server_prefer_ciphers`

Default	`client`
Value	string
Allowed Values	`clientserver`
See Also	`ssl` SSL configuration

Whether to give preference to the server's cipher list over a client's list.

`ssl_server_request_client_cert`

Default	`no`
Value	string
Allowed Values	`noyesany-cert`
See Also	`ssl` `auth_ssl_require_client_cert` SSL configuration
Changes	Changed: 2.4.0 Renamed from `ssl_verify_client_cert` setting.

If enabled, the imap/pop3/etc. client is requested to send an SSL certificate.

You can accept any certificate with 'any-cert' value, but you must configure authentication to check the client certificate with check_client_fp (or variant) extra field. See passdb: check_client_fp Extra field.

Note: This setting doesn't yet require the certificate to be valid or to even exist. See auth_ssl_require_client_cert.

`ssl_server_require_crl`

Default	`yes`
Value	boolean
See Also	`ssl` `ssl_server_ca_file` SSL configuration

If enabled, the CRL check must succeed for presented SSL client certificate and any intermediate certificates. The CRL list is generally appended to the ssl_server_ca_file file.

`stats_server`

Value	Named Filter

Filter for stats server specific settings.

`stats_writer_socket_path`

Default	`stats-writer`
Value	string

The path to the stats-writer socket.

`submission_add_received_header`

Default	`yes`
Value	boolean
Changes	Added: 2.4.0

Controls if "Received:" header should be added to mails by the submission backend.

`submission_client_workarounds`

Default	[None]
Value	Boolean List

Configures the list of active workarounds for Submission client bugs.

Supported workaround identifiers are:

implicit-auth-external: Implicitly login using the EXTERNAL SASL mechanism upon the first MAIL command, provided that the client provides a valid TLS client certificate. This is helpful for clients that omit explicit SASL authentication when configured for authentication using a TLS certificate (Thunderbird for example).
mailbox-for-path: Allow using bare Mailbox syntax (i.e., without <...>) instead of full path syntax.
whitespace-before-path: Allow one or more spaces or tabs between 'MAIL FROM:' and path and between 'RCPT TO:' and path.

`submission_host`

Default	[None]
Value	URL

Use this SMTP submission host to send messages.

Overrides sendmail_path value, if set.

`submission_logout_format`

Default	`in=%{input} out=%{output}`
Value	String without variables

The SMTP Submission logout format string.

Variables supported, including Mail user variables:

Variable Name	Description
`%{input}`	Bytes read from client
`%{output}`	Bytes sent to client
`%{command_count}`	Number of commands received from client
`%{reply_count}`	Number of replies sent to client
`%{transaction_id}`	ID of the current transaction, if any

`submission_max_mail_size`

Default	`40M`
Value	size

The maximum message size accepted for relay.

This value is announced in the SMTP SIZE capability.

If empty, this value is either determined from the relay server or left unlimited if no limit is known; the relay MTA will reply with error if some unknown limit exists there, which will be passed back to the client.

`submission_max_recipients`

Default	`unlimited`
Value	unsigned integer

Maximum number of recipients accepted per connection.

`submission_relay_command_timeout`

Default	`5mins`
Value	time (milliseconds)

Timeout for SMTP commands issued to the submission service's relay server.

The timeout is reset every time more data is being sent or received.

`submission_relay_connect_timeout`

Default	`30secs`
Value	time (milliseconds)

Timeout for connecting to and logging into the submission service's relay server.

`submission_relay_host`

Default	[None]
Value	string

Host of the relay server (REQUIRED to provide the submission service).

`submission_relay_master_user`

Default	[None]
Value	string

Master user name for authentication to the relay MTA if authentication is required.

`submission_relay_max_idle_time`

Default	`29mins`
Value	time

Submission relay max idle time for connection to relay MTA.

`submission_relay_password`

Default	[None]
Value	string

Password for authentication to the relay MTA if authentication is required.

`submission_relay_port`

Default	`25`
Value	Port Number

Port for the submission relay server.

`submission_relay_rawlog_dir`

Default	[None]
Value	directory path
See Also	rawlog
Changes	Changed: 2.4.6 Setting type changed.

Write protocol logs for relay connection to this directory for debugging.

Mail user variables can be used.

`submission_relay_ssl`

Default	`no`
Value	string
Allowed Values	`nosmtpsstarttls`

If enabled, SSL/TLS is used for the connection to the relay server.

Available values:

no: No SSL connection is used.
smtps: An SMTPS connection (immediate SSL) is used.
starttls: The STARTTLS command is used to establish the TLS layer.

`submission_relay_ssl_verify`

Default	`yes`
Value	boolean

If enabled, TLS certificate of the relay server must be verified.

`submission_relay_trusted`

Default	`no`
Value	boolean

If enabled, the relay server is trusted.

Determines whether we try to send (Postfix-specific) XCLIENT data to the relay server (only if enabled).

`submission_relay_user`

Default	[None]
Value	string

User name for authentication to the relay MTA if authentication is required.

`submission_ssl`

Default	`no`
Value	string
Allowed Values	`nosmtpsstarttls`
See Also	`submission_host`

If enabled, use SSL/TLS to connect to submission_host.

Available values:

no: No SSL connection is used.
smtps: An SMTPS connection (immediate SSL) is used.
starttls: The STARTTLS command is used to establish the TLS layer.

`submission_timeout`

Default	`30secs`
Value	time
See Also	`submission_host`

Timeout for submitting outgoing messages.

`syslog_facility`

Default	`mail`
Value	string

The syslog facility used if you're logging to syslog.

`textcat_config_path`

Default	`<textcat dir>`
Value	string
See Also	`language` `textcat_filter_languages`
Plugin	fts plugin

Path to the textcat/exttextcat configuration file, which lists the supported languages.

With textcat_filter_languages = yes (default) only the languages listed in language are loaded from this file, so there is normally no need to create a minimal version of the configuration file.

Example:

textcat_config_path = /usr/share/libexttextcat/fpdb.conf

`textcat_filter_languages`

Default	`yes`
Value	boolean
See Also	`language` `textcat_config_path`
Plugin	fts plugin
Changes	Added: 2.4.6

If enabled, language detection uses only the fingerprints of the languages listed in language from the textcat_config_path file. The textcat configuration file contains fingerprints for a large number of languages, and comparing the text against all of them takes most of the language detection CPU time.

Text in a language that isn't listed in language is detected as the closest listed language. If disabled, all fingerprints in the textcat configuration file are used, and such text is usually detected as an unknown language, which uses the default language (see language_default).

The filtered configuration is written to a temporary file in mail_temp_dir, which is deleted right after the textcat library has read it.

The default is no if dovecot_config_version is older than the version where this setting was added.

`trash_priority`

Default	[None]
Value	unsigned integer
Plugin	trash plugin

If non-zero, enables the trash plugin for the mailbox with the specified priority. Mailboxes with smaller priority number are emptied before mailboxes with a larger priority number. If there are multiple mailboxes with the same priority, expunge the oldest mail from them first.

Example where Trash is emptied before Spam:

namespace inbox {
  mailbox Trash {
    trash_priority = 1
  }
  mailbox Spam {
    trash_priority = 2
  }
}

`unix_listener`

Default	[None]
Value	Named List Filter
See Also	`service` `unix_listener_path`

Creates a new UNIX listener for a service. The filter name refers to the unix_listener_path setting.

`unix_listener_group`

Default	[None]
Value	string

Group of the listener file. Empty (default) means GID 0 (root/wheel).

`unix_listener_mode`

Default	`0600`
Value	octal unsigned integer

Mode of the file. Note that 0600 is an octal value, while 600 is a different decimal value. Setting mode to 0 disables the listener.

`unix_listener_path`

Default	[None]
Value	String without variables
See Also	`base_dir` `unix_listener`

Path to the UNIX socket file, relative to base_dir setting. The unix_listener filter name refers to this setting.

`unix_listener_type`

Default	[None]
Value	string
Changes	Added: 2.4.0

Listener type. This string value has service-specific meaning and is used to distinguish different listener types that one service may employ.

`unix_listener_user`

Default	[None]
Value	string

Owner of the listener file. Empty (default) means UID 0 (root).

`userdb`

Default	[None]
Value	Named List Filter
Dependencies	`userdb_driver`
See Also	userdb `userdb_name` `userdb_driver`

Creates a new userdb. The filter name refers to the userdb_name setting.

`userdb_driver`

Default	[None]
Value	string
See Also	`userdb_name` userdb Authentication Databases

The driver used for this user database. If empty, defaults to userdb_name.

`userdb_fields`

Default	[None]
Value	String List
See Also	userdb: Extra Fields

Userdb fields (and userdb: Extra Fields). The values can contain %variables. All %variables used here reflect the state after the current userdb lookup, and can refer to fields returned by previous userdb lookups. Depending on the userdb driver, it can also refer to variable fields returned by it (e.g. %{ldap:fieldName}).

INFO

The LDAP driver provides additional specific variables, see LDAP authentication for more details.

For example:

userdb ldap {
  fields {
    user = %{ldap:userId}
    home = /home/%{ldap:mailboxPath}
    uid = vmail
    gid = vmail
  }
}

`userdb_fields_import_all`

Default	`yes` For `userdb ldap` the default is `no`.
Value	boolean
See Also	`userdb_fields`

If yes, import all fields returned by the userdb lookup. If no, require userdb_fields to explicitly add wanted fields.

`userdb_ldap_filter`

Default	[None]
Value	string

Filter for userdb lookup.

Variables that can be used (see Settings variables for full list).

Example:

userdb ldap {
  filter = (&(objectClass=posixAccount)(uid=%{user}))
  #...
}

`userdb_ldap_iterate_fields`

Default	[None]
Value	String List

Attributes to get a list of all users. Currently only the attribute user is supported.

Example:

userdb ldap {
  iterate_filter = (objectClass=smiMessageRecipient)
  iterate_fields {
    user = %{ldap:mailRoutingAddress}
  }
}

`userdb_ldap_iterate_filter`

Default	[None]
Value	string

Filter to get a list of all users.

userdb ldap {
  iterate_filter = (objectClass=smiMessageRecipient)
  iterate_fields {
    user = %{ldap:mailRoutingAddress}
  }
}

`userdb_name`

Default	[None]
Value	string
See Also	`userdb` `userdb_driver`

Name of the userdb. The userdb filter name refers to this setting. If the userdb_driver setting is empty, the userdb_name is used as the driver. This allows doing e.g.:

userdb passwd-file {
  passwd_file_path = /etc/dovecot/passwd

`userdb_result_failure`

Default	`continue`
Value	string
Allowed Values	`return-okreturnreturn-failcontinuecontinue-okcontinue-fail`
See Also	userdb: Result Values

What to do if the user was not found from the userdb. Possible values and their meaning are described fully at userdb: Result Values.

`userdb_result_internalfail`

Default	`continue`
Value	string
Allowed Values	`return-okreturnreturn-failcontinuecontinue-okcontinue-fail`
See Also	userdb: Result Values

What to do after the userdb failed due to an internal error. Possible values and their meaning are described fully at userdb: Result Values. If any of the userdbs had an internal failure and the final userdb also returns continue the authentication will fail with internal error.

`userdb_result_success`

Default	`return-ok`
Value	string
Allowed Values	`return-okreturnreturn-failcontinuecontinue-okcontinue-fail`
See Also	userdb: Result Values

What to do if the user was successfully found from the userdb. Possible values and their meaning are described fully at userdb: Result Values.

`userdb_skip`

Default	`never`
Value	string
Allowed Values	`neverfoundnotfound`

Configures when userdbs should be skipped:

Value	Description
`never`	Never skip over this userdb.
`found`	Skip if an earlier userdbs already found the user.
`notfound`	Skip if previous userdbs haven't yet found the user.

`userdb_sql_iterate_query`

Default	[None]
Value	string
Changes	Changed: 2.4.6 `%{variable}` values are now sent to the database as bind parameters instead of being expanded into the query text. See Variables in Queries for the resulting restrictions.

SQL query to list all available usernames.

`userdb_sql_query`

Default	[None]
Value	string
Changes	Changed: 2.4.6 `%{variable}` values are now sent to the database as bind parameters instead of being expanded into the query text. See Variables in Queries for the resulting restrictions.

SQL query to lookup the userdb fields.

`userdb_static_allow_all_users`

Default	`no`
Value	boolean
Changes	Added: 2.4.0

Skip user existence verification via passdb lookup.

`userdb_use_worker`

Default	`no` specific userdb have different defaults
Value	boolean

If yes, run the userdb lookup in auth-worker process instead of the main auth process. This setting is only used by some of the userdb drivers.

`valid_chroot_dirs`

Default	[None]
Value	Boolean List

List of directories under which chrooting is allowed for mail processes.

Addresses the risk of root exploits enabled by incorrect use of chrooting.

Interpretation is recursive, so including /var/mail allows chrooting to subdirectories such as /var/mail/foo/bar.

`verbose_proctitle`

Default	`no`
Value	boolean

If enabled, the ps command shows more verbose process details, including the username and IP address of the connected client.

This aids in seeing who is actually using the server, as well as helps debugging in case there are any problems. See process titles.

`verbose_ssl`

Default	`no`
Value	boolean
Changes	Removed: 2.4.0

If enabled, protocol-level SSL errors are logged. Same as log_debug = category=ssl.

`version_ignore`

Default	`no`
Value	boolean

If enabled, ignore version mismatches between different Dovecot versions.

`welcome_script`

Value	Named Filter
See Also	welcome
Plugin	welcome plugin

Named filter for configuring the welcome execute script.

welcome {
  execute welcome {
    args = %{user}
  }

`welcome_wait`

Default	`no`
Value	boolean
See Also	welcome
Plugin	welcome plugin

If enabled, wait for the script to finish. By default, the welcome script is run asynchronously.

Advanced Settings

DANGER

These settings should not normally be changed.

`auth_master_socket_path`

Default	`auth-master`
Value	string
Advanced Setting; this should not normally be changed.

The UNIX socket path to the master authentication server for finishing user logins.

It is usually neither necessary nor advisable to change the default.

`auth_policy_hash_truncate`

Default	`12`
Value	unsigned integer
See Also	`auth_policy_server_url`
Advanced Setting; this should not normally be changed.

How many bits to use from password hash when reporting to policy server.

`auth_proxy_self`

Default	[None]
Value	string
Advanced Setting; this should not normally be changed.

If the destination for proxying matches any of the IP addresses listed here, proxying is not performed when proxy_maybe=yes is returned.

This parameter isn't normally needed; its main use is if the destination IP address belongs to, for instance, a load-balancer rather than the server itself.

`auth_socket_path`

Default	`auth-userdb`
Value	string
Advanced Setting; this should not normally be changed.

The UNIX socket path to the master authentication server for finding users.

It is usually neither necessary nor advisable to change the default.

`auth_username_translation`

Default	[None]
Value	string
Advanced Setting; this should not normally be changed.

If set, performs username character translations before querying the auth database.

The value is a string formed of sets of from and to characters alternating.

A value of #@/@ means that # and / will both be translated to the @ character.

`base_dir`

Default	`/var/run/dovecot/`
Value	string
Advanced Setting; this should not normally be changed.

The base directory in which Dovecot should store runtime data.

This can be used to override the base directory determined at compile time.

`dns_client_socket_path`

Default	`dns-client`
Value	string
Advanced Setting; this should not normally be changed.

UNIX socket path to the dns-client service.

`dsync_hashed_headers`

Default	`Date Message-ID`
Value	string
Advanced Setting; this should not normally be changed.

Which email headers are used in incremental syncing for checking whether the local email matches the remote email?

Format: a space-separated list of headers.

This list should only include headers that can be efficiently downloaded from the remote server.

`fs_posix_accurate_mtime`

Default	`no`
Value	boolean
Advanced Setting; this should not normally be changed.

Configure whether utimes() is called after writes to guarantee microsecond precision timestamps for files. By default Linux updates the mtime only on timer interrupts, which is not remotely close to microsecond precision.

`fs_posix_autodelete_empty_directories`

Default	`no`
Value	boolean
Advanced Setting; this should not normally be changed.

If the last file in a directory is deleted, should the parent directory be automatically deleted?

INFO

Using this setting makes the POSIX filesystem behave more like an object storage would.

WARNING

This setting can cause the POSIX filesystem to also delete the parent directory hierarchy farther up than anticipated.

`fs_posix_lock_method`

Default	`flock`
Value	string
Allowed Values	`flockdotlock`
Advanced Setting; this should not normally be changed.

Lock method to use for locking files. Currently nothing uses lib-fs locking.

`fts_flatcurve_commit_limit`

Default	`500`
Value	unsigned integer
Plugin	fts-flatcurve plugin
Advanced Setting; this should not normally be changed.

Commit database changes after this many documents are updated. Higher commit limits will result in faster indexing for large transactions (i.e. indexing a large mailbox) at the expense of high memory usage. The default value should be sufficient to allow indexing in a 256 MB maximum size process.

Set to 0 to use the Xapian default.

`fts_flatcurve_min_term_size`

Default	`2`
Value	unsigned integer
Plugin	fts-flatcurve plugin
Advanced Setting; this should not normally be changed.

The minimum number of characters in a term to index.

`fts_flatcurve_optimize_density_percentage`

Default	`25`
Value	unsigned integer
See Also	`fts_flatcurve_rotate_count`
Plugin	fts-flatcurve plugin
Advanced Setting; this should not normally be changed.

When an index shard's message count falls below this percentage of fts_flatcurve_rotate_count, the mailbox is scheduled for deferred optimization. This helps prevent accumulation of sparse shards that degrade mailbox open performance.

Set to 0 to disable density-based optimization.

This optimization requires fts_flatcurve_rotate_count to be enabled.

`fts_flatcurve_optimize_limit`

Default	`10`
Value	unsigned integer
Plugin	fts-flatcurve plugin
Advanced Setting; this should not normally be changed.

Once the database reaches this number of shards, automatically optimize the DB at shutdown.

Set to 0 to disable auto-optimization.

`fts_flatcurve_rotate_count`

Default	`5000`
Value	unsigned integer
Plugin	fts-flatcurve plugin
Advanced Setting; this should not normally be changed.

When the "current" fts database reaches this number of messages, it is rotated to a read-only database and replaced by a new write DB. Most people should not change this setting.

Set to 0 to disable rotation.

`fts_flatcurve_rotate_time`

Default	`5s`
Value	time (milliseconds)
Plugin	fts-flatcurve plugin
Advanced Setting; this should not normally be changed.

When the "current" fts database exceeds this length of time (in msecs) to commit changes, it is rotated to a read-only database and replaced by a new write DB. Most people should not change this setting.

Set to 0 to disable rotation.

`http_client_auto_redirect`

Default	`yes`
Value	boolean
See Also	`http_client_request_max_redirects`
Changes	Added: 2.4.0
Advanced Setting; this should not normally be changed.

If this setting is yes redirects are handled as long as http_client_request_max_redirects isn't reached. If no the redirect responses are handled as regular failure responses.

WARNING

This setting should likely be changed only in the code, never in configuration.

`http_client_auto_retry`

Default	`yes`
Value	boolean
See Also	`http_client_request_max_attempts`
Changes	Added: 2.4.0
Advanced Setting; this should not normally be changed.

If this setting is no requests are not automatically retried by the generic HTTP client code. It's still possible to retry the requests with explicit http_client_request_try_retry() calls as long as http_client_request_max_attempts isn't reached.

WARNING

This setting should likely be changed only in the code, never in configuration.

`http_client_connect_backoff_max_time`

Default	`1 min`
Value	time (milliseconds)
Changes	Added: 2.4.0
Advanced Setting; this should not normally be changed.

Maximum backoff time for retries.

`http_client_connect_backoff_time`

Default	`100 ms`
Value	time (milliseconds)
Changes	Added: 2.4.0
Advanced Setting; this should not normally be changed.

Initial backoff time for retries. It's doubled at each connection failure.

`http_client_dns_ttl`

Default	`30 mins`
Value	time (milliseconds)
Changes	Added: 2.4.0
Advanced Setting; this should not normally be changed.

How long to cache DNS entries.

`http_client_max_auto_retry_delay`

Default	[None]
Value	time
Changes	Added: 2.4.0
Advanced Setting; this should not normally be changed.

Maximum acceptable delay for automatically retrying/redirecting requests. If a server sends a response with a Retry-After header that causes a delay longer than this, the request is not automatically retried and the response is returned.

`http_client_response_hdr_max_field_size`

Default	`8k`
Value	size
Changes	Added: 2.4.0
Advanced Setting; this should not normally be changed.

Response header limit: Max size for an individual field.

`http_client_response_hdr_max_fields`

Default	`50`
Value	unsigned integer
Changes	Added: 2.4.0
Advanced Setting; this should not normally be changed.

Response header limit: Max number of fields.

`http_client_response_hdr_max_size`

Default	`200k`
Value	size
Changes	Added: 2.4.0
Advanced Setting; this should not normally be changed.

Response header limit: Max size for the entire response header.

`http_client_socket_recv_buffer_size`

Default	[None]
Value	size
Changes	Added: 2.4.0
Advanced Setting; this should not normally be changed.

The kernel receive buffer size for the connection sockets. 0 = kernel defaults.

`http_client_socket_send_buffer_size`

Default	[None]
Value	size
Changes	Added: 2.4.0
Advanced Setting; this should not normally be changed.

The kernel send buffer size for the connection sockets. 0 = kernel defaults.

`http_client_soft_connect_timeout`

Default	[None]
Value	time (milliseconds)
Changes	Added: 2.4.0
Advanced Setting; this should not normally be changed.

Time to wait for TCP connect and SSL handshake to finish for the first connection before trying the next IP in parallel. 0 = wait until current connection attempt finishes.

`http_client_user_agent`

Default	[None]
Value	string
Changes	Added: 2.4.0
Advanced Setting; this should not normally be changed.

User-Agent: header to send.

`http_server_default_host`

Default	[None]
Value	string
Advanced Setting; this should not normally be changed.

Overwrite the local hostname with http_server_default_host.

`http_server_max_payload_size`

Default	`10G`
Value	size
Advanced Setting; this should not normally be changed.

Request payload limit: Max size for the request payload.

`http_server_max_target_length`

Default	`8k`
Value	size
Advanced Setting; this should not normally be changed.

Request target limit: Maximum length of the request target.

`http_server_request_hdr_max_field_size`

Default	`8k`
Value	size
Advanced Setting; this should not normally be changed.

Request header limit: Max size for an individual field.

`http_server_request_hdr_max_fields`

Default	`50`
Value	unsigned integer
Advanced Setting; this should not normally be changed.

Request header limit: Max number of fields.

`http_server_request_hdr_max_size`

Default	`200k`
Value	size
Advanced Setting; this should not normally be changed.

Request header limit: Max size for the entire request header.

`http_server_socket_recv_buffer_size`

Default	[None]
Value	size
Advanced Setting; this should not normally be changed.

The kernel receive buffer size for the connection sockets. 0 = kernel defaults.

`http_server_socket_send_buffer_size`

Default	`0`
Value	size
Advanced Setting; this should not normally be changed.

The kernel send buffer size for the connection sockets. 0 = kernel defaults.

`imap_compress_on_proxy`

Default	`yes`
Value	boolean
See Also	`login_trusted_networks`
Changes	Added: 2.4.2 Changed: 2.4.5 Changed from `no` to `yes`.
Advanced Setting; this should not normally be changed.

If enabled, the IMAP COMPRESS (RFC 4978) extension is handled by the Dovecot proxy instead of the backend's imap process when the client connection comes through a Dovecot proxy. This moves the compression work from the backend to the proxy.

This setting must be set on the backend, not on the proxy. For this to work, login_trusted_networks on the backend must be set to point to the proxy.

`imap_idle_notify_interval`

Default	`2mins`
Value	time
Advanced Setting; this should not normally be changed.

The amount of time to wait between "OK Still here" untagged IMAP responses when the client is in IDLE operation.

`imap_max_line_length`

Default	`64k`
Value	size
Advanced Setting; this should not normally be changed.

Maximum IMAP command line length. Some clients generate very long command lines with huge mailboxes, so you may need to raise this if you get Too long argument or IMAP command line too large errors often.

`language_tokenizer_kuromoji_split_compounds`

Default	`yes`
Value	boolean
See Also	FTS Tokenization
Plugin	fts plugin
Advanced Setting; this should not normally be changed.

This setting enables search mode in the Atilika Kuromoji library. The setting defaults to enabled and should not be changed unless there is a compelling reason.

WARNING

If this setting is changed, existing FTS indexes will produce unexpected results. The FTS indexes should be recreated in this case.

`libexec_dir`

Default	`/usr/libexec/dovecot`
Value	string
Advanced Setting; this should not normally be changed.

The directory from which you execute commands via doveadm-exec.

`lmtp_verbose_replies`

Default	`no`
Value	boolean
Advanced Setting; this should not normally be changed.

This setting makes the replies returned to the client much more verbose. Currently, this only applies when the LMTP proxy is involved, for which e.g. backend connection errors are returned in full detail.

Normally, these errors are replaced by a more generic error message to prevent leaking system details to the clients (e.g. IP addresses and ports). It is therefore not recommended to enable this setting beyond troubleshooting efforts.

`login_greeting`

Default	`Dovecot ready.`
Value	string
Advanced Setting; this should not normally be changed.

The greeting message displayed to clients.

Variables allowed:

LMTP: Mail service user variables
Other Protocols: Login variables

`login_proxy_notify_path`

Default	`proxy-notify`
Value	string
Advanced Setting; this should not normally be changed.

Path to proxy-notify pipe.

`login_socket_path`

Default	[None]
Value	string
Changes	Added: 2.4.0
Advanced Setting; this should not normally be changed.

Default socket path for all services' login processes. Can be overridden by passing a parameter to the login executable.

`mail_cache_max_header_name_length`

Default	`100`
Value	unsigned integer
Changes	Added: 2.4.0
Advanced Setting; this should not normally be changed.

Maximum header name length stored in the cache, where 0 stands for unlimited (which is also the former behavior).

When enabled, the cache truncates the names to this length in memory and on file. While the header name remains unchanged in the storage, all the headers sharing the first mail_cache_max_header_name_length prefix characters are de facto aliased and will be considered as the same header on cache fetch.

Also, attempting to fetch a specific aliased header will succeed even if the header does not actually exist (this does NOT happen when the feature is disabled with explicitly with mail_cache_max_header_name_length = unlimited)

Example: (mail_cache_max_header_name_length = 5)

If the mail contains the header X-name: value, attempting to fetch X-nam or X-names will also produce X-name: value as a result (with the original header name, not the requested one).

Trying to fetch the mail text or the mail headers will properly return only X-name: value.

`mail_cache_max_headers_count`

Default	`100`
Value	unsigned integer
Changes	Added: 2.4.0
Advanced Setting; this should not normally be changed.

Maximum number of headers in yes/temp cache decision before the cache refuses to promote more header decisions from no to temp, where 0 stands for unlimited (which is also the former behavior).

When entries are rejected, the event mail_cache_decision_rejected is emitted.

Also, while the cache's headers count is saturated, the effective value of mail_cache_unaccessed_field_drop is reduced to 1/4 of of the specified one, in order to aid the cache to return within the limits.

`mail_cache_max_size`

Default	`1G`
Value	size
Advanced Setting; this should not normally be changed.

If dovecot.index.cache becomes larger than this, it's truncated to empty size.

WARNING

The maximum value is 1 GB because the cache file format can't currently support larger sizes.

`mail_cache_min_mail_count`

Default	[None]
Value	unsigned integer
Advanced Setting; this should not normally be changed.

Only update cache file when the mailbox contains at least this many messages.

With a setting other than 0, you can optimize behavior for fewer disk writes at the cost of more disk reads.

`mail_cache_purge_continued_percentage`

Default	`200`
Value	unsigned integer
Advanced Setting; this should not normally be changed.

Compress the cache file when n% of records are deleted (by count, not by size).

For example 200 means that the record has 2 continued rows, i.e. it exists in 3 separate segments in the cache file.

`mail_cache_purge_delete_percentage`

Default	`20`
Value	unsigned integer
Advanced Setting; this should not normally be changed.

Compress the cache file when n% of records are deleted (by count, not by size).

`mail_cache_purge_header_continue_count`

Default	`4`
Value	unsigned integer
Advanced Setting; this should not normally be changed.

Compress the cache file when we need to follow more than n next_offsets to find the latest cache header.

`mail_cache_purge_min_size`

Default	`32k`
Value	size
Advanced Setting; this should not normally be changed.

Only compress cache file if it is larger than this size.

`mail_cache_record_max_size`

Default	`64k`
Value	size
Advanced Setting; this should not normally be changed.

If a cache record becomes larger than this, don't add it to the cache file.

`mail_cache_unaccessed_field_drop`

Default	`30days`
Value	time
See Also	mail cache configuration
Advanced Setting; this should not normally be changed.

Specifies when cache decisions are downgraded.

Change caching decision from YES to TEMP after this much time has passed. Drop the field entirely after twice this much time has passed, regardless of whether the cache decision was YES or TEMP previously.

If the cache header count is capped to mail_cache_max_headers_count then the effective value is reduced to 1/4 of the configured value until enough headers expire for the cache to fall back inside the limits.

`mail_ext_attachment_hash`

Default	`%{sha1}`
Value	string
Allowed Values	`%{md4}%{md5}%{sha1}%{sha256}%{sha512}%{size}`
See Also	`mail_ext_attachment_path`
Advanced Setting; this should not normally be changed.

The hash format to use in attachment filenames when saving attachments externally.

Variables and additional text can be included in this string.

The syntax allows truncation of any variable. For example %{sha256:80} will return only the first 80 bits of the SHA256 output.

`mail_full_filesystem_access`

Default	`no`
Value	boolean
See Also	`mailbox_list_validate_fs_names`
Advanced Setting; this should not normally be changed.

Allow full filesystem access to clients?

If enabled, no access checks are performed other than what the operating system does for the active UID/GID. This also disables the mailbox_list_validate_fs_names setting.

This setting works with both Maildir and mbox, allowing you to prefix mailbox names with /path/ or ~user/ indicators.

`mail_index_log2_max_age`

Default	`2days`
Value	time
Advanced Setting; this should not normally be changed.

Delete .log.2 index file when older than this value.

Older .log.2 files are useful for QRESYNC and dsync, so this value should not be too low.

`mail_index_log_rotate_max_size`

Default	`1M`
Value	size
See Also	`mail_index_log_rotate_min_age` `mail_index_log_rotate_min_size`
Advanced Setting; this should not normally be changed.

Always rotate transaction log after it exceeds this size.

`mail_index_log_rotate_min_age`

Default	`5mins`
Value	time
See Also	`mail_index_log_rotate_max_size`
Advanced Setting; this should not normally be changed.

Rotate transaction log if it is older than this value and is larger than mail_index_log_rotate_min_size.

`mail_index_log_rotate_min_size`

Default	`32k`
Value	size
Advanced Setting; this should not normally be changed.

Rotate transaction log if it is larger than this size and is older than mail_index_log_rotate_min_age.

`mail_index_rewrite_max_log_bytes`

Default	`128k`
Value	size
See Also	`mail_index_rewrite_min_log_bytes`
Advanced Setting; this should not normally be changed.

Rewrite the index when the number of bytes that needs to be read from the .log index file on refresh is between these min/max values.

`mail_index_rewrite_min_log_bytes`

Default	`8k`
Value	size
See Also	`mail_index_rewrite_max_log_bytes`
Advanced Setting; this should not normally be changed.

Rewrite the index when the number of bytes that needs to be read from the .log index file on refresh is between these min/max values.

`mail_max_keyword_length`

Default	`50`
Value	unsigned integer
Advanced Setting; this should not normally be changed.

The maximum length allowed for a mail keyword name.

Compliance is enforced only during attempts to create new keywords.

`mail_save_crlf`

Default	`no`
Value	boolean
Advanced Setting; this should not normally be changed.

Save message with CR+LF line endings?

Messages are normally saved with LF line endings.

Enabling this makes saving messages less CPU-intensive, especially with the sendfile() system call used in Linux and FreeBSD. However, enabling comes at the cost of slightly increased disk I/O, which could decrease the speed in some deployments.

`mailbox_idle_check_interval`

Default	`30secs`
Value	time
Advanced Setting; this should not normally be changed.

The minimum time between checks for new mail/other changes when a mailbox is in the IMAP IDLE state.

`mailbox_subscriptions_filename`

Default	`subscriptions` specific Mailbox Formats have different defaults
Value	string
Advanced Setting; this should not normally be changed.

Specifies the filename used for storing mailbox subscriptions.

`managesieve_client_workarounds`

Default	[None]
Value	Boolean List
Advanced Setting; this should not normally be changed.

Enables various workarounds for ManageSieve clients. Currently there are none.

`managesieve_implementation_string`

Default	`Dovecot Pigeonhole`
Value	string
Advanced Setting; this should not normally be changed.

Sets the ManageSieve implementation string returned by the IMPLEMENTATION capability.

`managesieve_max_compile_errors`

Default	`5`
Value	unsigned integer
Advanced Setting; this should not normally be changed.

The maximum number of compile errors that are returned to the client upon script upload or script verification.

`managesieve_max_line_length`

Default	`64k`
Value	size
Advanced Setting; this should not normally be changed.

The maximum ManageSieve command line length in bytes.

Since long command lines are very unlikely with ManageSieve, changing this will generally not be useful.

`managesieve_notify_capability`

Default	`<dynamically determined>`
Value	Boolean List
Advanced Setting; this should not normally be changed.

NOTIFY capabilities reported by the ManageSieve service before authentication.

This does normally not need to be configured. If left unassigned, these will be assigned dynamically according to what the Sieve interpreter is configured to support using the global sieve_extensions setting (after login this may differ depending on the settings applicable to the authenticated user).

`managesieve_sieve_capability`

Default	`<dynamically determined>`
Value	Boolean List
Advanced Setting; this should not normally be changed.

SIEVE capabilities reported by the ManageSieve service before authentication.

`mbox_md5`

Default	`apop3d`
Value	string
Allowed Values	`apop3dall`
See Also	`pop3_uidl_format` mbox
Advanced Setting; this should not normally be changed.

The mail-header selection algorithm to use for MD5 POP3 UIDLs when the setting pop3_uidl_format = %{md5} is applied.

`mbox_min_index_size`

Default	[None]
Value	size
See Also	mbox
Advanced Setting; this should not normally be changed.

For mboxes smaller than this size, index files are not written.

If an index file already exists, it gets read but not updated.

The default should not be changed for most installations.

`quota_clone_unset`

Default	`no`
Value	boolean
Plugin	quota-clone plugin
Changes	Added: 2.4.0
Advanced Setting; this should not normally be changed.

Unset quota information before updating. This is needed with some dict drivers that do not support upserting, such as SQL with older SQLite.

`service_privileged_group`

Default	[None]
Value	string
See Also	`mail_privileged_group`
Advanced Setting; this should not normally be changed.

Secondary UNIX group - which is disabled by default - but can be enabled by the process. mail_privileged_group setting is a more user friendly way to use this setting for mail processes.

`sieve_duplicate_default_period`

Default	`14d`
Value	time
See Also	Sieve duplicate extension
Plugin	sieve plugin
Advanced Setting; this should not normally be changed.

Default period after which tracked values are purged from the duplicate tracking database.

`sieve_duplicate_max_period`

Default	`7d`
Value	time
See Also	Sieve duplicate extension
Plugin	sieve plugin
Advanced Setting; this should not normally be changed.

Maximum period after which tracked values are purged from the duplicate tracking database.

`sieve_include_max_includes`

Default	`255`
Value	unsigned integer
See Also	Sieve include extension
Plugin	sieve plugin
Advanced Setting; this should not normally be changed.

The maximum number of scripts that may be included. This is the total number of scripts involved in the include tree.

`sieve_include_max_nesting_depth`

Default	`10`
Value	unsigned integer
See Also	Sieve include extension
Plugin	sieve plugin
Advanced Setting; this should not normally be changed.

The maximum nesting depth for the include tree.

`sieve_max_script_size`

Default	`1M`
Value	size
Plugin	sieve plugin
Advanced Setting; this should not normally be changed.

The maximum size of a Sieve script. The compiler will refuse to compile any script larger than this limit.

If set to 0, no limit on the script size is enforced.

`sieve_notify_mailto_max_headers`

Default	`16`
Value	unsigned integer
See Also	`sieve_notify_mailto_max_recipients` Sieve notifications extensions
Plugin	sieve plugin
Changes	Added: 2.4.5 Setting to limit the number of additional headers per mailto notification is added.
Advanced Setting; this should not normally be changed.

The maximum number of additional headers a single mailto: notify action may specify in its URI.

0 means no limit on the number of headers is enforced.

`sieve_notify_mailto_max_recipients`

Default	`8`
Value	unsigned integer
See Also	`sieve_notify_mailto_max_headers` Sieve notifications extensions
Plugin	sieve plugin
Changes	Added: 2.4.5 Setting to limit the number of recipients per mailto notification is added.
Advanced Setting; this should not normally be changed.

The maximum number of recipients a single mailto: notify action may specify, counted across the URI and any to/cc/bcc headers.

0 means no limit on the number of recipients is enforced.

`sieve_notify_max_notifications`

Default	`10`
Value	unsigned integer
See Also	`sieve_max_actions` `sieve_max_redirects` Sieve notifications extensions
Plugin	sieve plugin
Changes	Added: 2.4.5 Setting to limit maximum number of notifications per script is added.
Advanced Setting; this should not normally be changed.

The maximum number of notify actions (RFC 5435) that can be performed during a single script execution.

0 means notify is prohibited; scripts using the notify command will fail to compile with "local policy prohibits the use of a notify action".

Note that this is independent of sieve_max_redirects; the redirect action and the notify mailto method are governed by separate limits.

The effective per-script limit on notify actions is min(sieve_notify_max_notifications, sieve_max_actions): when the total number of actions in a script reaches sieve_max_actions (default 32), execution aborts with "total number of actions exceeds policy limit" before this per-class limit is reached. To allow more than sieve_max_actions notify actions, raise that setting as well.

`sieve_variables_max_scope_count`

Default	`255`
Value	unsigned integer
See Also	Sieve variables extension
Plugin	sieve plugin
Advanced Setting; this should not normally be changed.

The maximum number of variables that can be declared in a scope.

There are currently two variable scopes: the normal script scope and the global scope created by the Sieve include extension.

The minimum value for this setting is 128.

`sieve_variables_max_value_size`

Default	`4k`
Value	size
See Also	Sieve variables extension
Plugin	sieve plugin
Advanced Setting; this should not normally be changed.

The maximum allowed size for the value of a variable. If exceeded at runtime, the value is always truncated to the configured maximum.

The minimum value for this setting is 4000 bytes.

`sqlite_busy_timeout`

Default	`1s`
Value	time (milliseconds)
Changes	Added: 2.4.5
Advanced Setting; this should not normally be changed.

Time to wait for a locked sqlite database to become available before giving up with an SQLITE_BUSY error. Even in write-ahead logging mode (see sqlite_journal_mode) only one writer runs at a time, so concurrent writers may need to wait. Increase this on slow storage where writes contend.

`state_dir`

Default	`/var/lib/dovecot`
Value	string
Advanced Setting; this should not normally be changed.

The compile-time directory PKG_STATEDIR (typically /var/lib/dovecot) is hard-coded as the location of state files. The PKG_STATEDIR value is taken as the default state_dir setting but can be overridden - for instance, if you wish to use the same binaries for a system daemon and a user daemon.

The settings state_dir = /home/foo/dovecot/state and base_dir = /home/foo/dovecot/run give an example of usage.

`virtual_max_open_mailboxes`

Default	`64`
Value	unsigned integer
Plugin	virtual plugin
Advanced Setting; this should not normally be changed.

How many mailboxes to open in virtual plugin.

Databases

Mechanisms

Users

Extensions

All Dovecot Settings ​

Settings ​

@mailbox_defaults

@metric_defaults

acl

acl_cache_ttl

acl_defaults_from_inbox

acl_dict_index

acl_driver

acl_global_path

acl_globals_only

acl_groups

acl_id

acl_ignore

acl_rights

acl_sharing_map

acl_user

apparmor_hats

auth_allow_cleartext

auth_allow_weak_schemes

auth_anonymous_username

auth_cache_negative_ttl

auth_cache_size

auth_cache_ttl

auth_cache_verify_password_with_worker

auth_debug

auth_debug_passwords

auth_default_domain

auth_failure_delay

auth_gssapi_hostname

auth_internal_failure_delay

auth_krb5_keytab

auth_master_user_separator

auth_mechanisms

auth_policy

auth_policy_check_after_auth

auth_policy_check_before_auth

auth_policy_hash_mech

auth_policy_hash_nonce

auth_policy_log_only

auth_policy_reject_on_fail

auth_policy_report_after_auth

auth_policy_request_attributes

auth_policy_server_api_header

auth_policy_server_url

auth_realms

auth_ssl_require_client_cert

auth_ssl_username_from_cert

auth_use_winbind

auth_username_chars

auth_username_format

auth_verbose

auth_verbose_passwords

auth_winbind_helper_path

cassandra_application_name

cassandra_application_version

cassandra_client_id

cassandra_connect_timeout

cassandra_connections_per_host

cassandra_debug_queries

cassandra_delete_consistency

cassandra_delete_fallback_consistency

cassandra_execution_retry_interval

cassandra_execution_retry_times

cassandra_fallback_failure_threshold

cassandra_fallback_window

cassandra_heartbeat_interval

cassandra_hosts

cassandra_idle_timeout

cassandra_io_thread_count

cassandra_keyspace

cassandra_latency_aware_exclusion_threshold

cassandra_latency_aware_min_measured

cassandra_latency_aware_retry_period

cassandra_latency_aware_routing

cassandra_latency_aware_scale

All Dovecot Settings

Settings

`@mailbox_defaults`

`@metric_defaults`

`acl`

`acl_cache_ttl`

`acl_defaults_from_inbox`

`acl_dict_index`

`acl_driver`

`acl_global_path`

`acl_globals_only`

`acl_groups`

`acl_id`

`acl_ignore`

`acl_rights`

`acl_sharing_map`

`acl_user`

`apparmor_hats`

`auth_allow_cleartext`

`auth_allow_weak_schemes`

`auth_anonymous_username`

`auth_cache_negative_ttl`

`auth_cache_size`

`auth_cache_ttl`

`auth_cache_verify_password_with_worker`

`auth_debug`

`auth_debug_passwords`

`auth_default_domain`

`auth_failure_delay`

`auth_gssapi_hostname`

`auth_internal_failure_delay`

`auth_krb5_keytab`

`auth_master_user_separator`

`auth_mechanisms`

`auth_policy`

`auth_policy_check_after_auth`

`auth_policy_check_before_auth`

`auth_policy_hash_mech`

`auth_policy_hash_nonce`

`auth_policy_log_only`

`auth_policy_reject_on_fail`

`auth_policy_report_after_auth`

`auth_policy_request_attributes`

`auth_policy_server_api_header`

`auth_policy_server_url`

`auth_realms`

`auth_ssl_require_client_cert`

`auth_ssl_username_from_cert`

`auth_use_winbind`

`auth_username_chars`

`auth_username_format`

`auth_verbose`

`auth_verbose_passwords`

`auth_winbind_helper_path`

`cassandra_application_name`

`cassandra_application_version`

`cassandra_client_id`

`cassandra_connect_timeout`

`cassandra_connections_per_host`

`cassandra_debug_queries`

`cassandra_delete_consistency`

`cassandra_delete_fallback_consistency`

`cassandra_execution_retry_interval`

`cassandra_execution_retry_times`

`cassandra_fallback_failure_threshold`

`cassandra_fallback_window`

`cassandra_heartbeat_interval`

`cassandra_hosts`

`cassandra_idle_timeout`

`cassandra_io_thread_count`

`cassandra_keyspace`

`cassandra_latency_aware_exclusion_threshold`

`cassandra_latency_aware_min_measured`

`cassandra_latency_aware_retry_period`

`cassandra_latency_aware_routing`

`cassandra_latency_aware_scale`

`cassandra_latency_aware_update_rate`

`cassandra_local_datacenter`

`cassandra_log_level`

`cassandra_log_retries`