All Dovecot Settings

Settings

acl

Default	[None]
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_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_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	Added: 2.4.0

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	[None]
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

Default	[None]
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.

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	[None]
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

Default	[None]
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_socket_path

Default	auth-userdb
Value	string

The UNIX socket path to the master authentication server for finding users.

It is usually neither necessary nor advisable to change the default.

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

Formatting applied to username before querying the auth database.

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

auth_worker_max_count

Default	[None]
Value	unsigned integer

Maximum number of dovecot-auth worker processes active.

The auth workers are used to execute blocking passdb and userdb queries (e.g., MySQL and PAM). They are automatically created and destroyed as necessary.

cassandra_connect_timeout

Default	5s
Value	time (milliseconds)

Connection timeout.

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	local-quorum
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

cassandra_execution_retry_times

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

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_routing

Default	no
Value	boolean

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

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_metrics

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	[None]
Value	Port Number

CQL port to use.

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

Read consistency if primary consistency fails.

cassandra_request_timeout

Default	60s
Value	time (milliseconds)

How long to wait for a query to finish.

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_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	local-quorum
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	[None]
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	[None]
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	[None]
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	[None]
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_private_keys

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

List of private keys to decrypt files. 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_keys 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_keys and crypt_user_key_encryption_key lists.

crypt_private_key_name

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

Name of the private key inside crypt_global_private_keys 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.

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

Example:

crypt_user_key_curve = secp521r1

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 setting and no key generation is performed.

In folder-keys mode, a key pair is generated for the user, and a folder-specific key pair is generated. The latter is encrypted by means of the user's key pair.

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	[None]
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. If empty new mails are not encrypted, but existing mails can still be decrypted.

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

Define the default internal 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_field

Default	[None]
Value	Named List Filter
See Also	dict_map_field_pattern

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

dict_map_field_name

Default	[None]
Value	string
See Also	dict_map_field

Field in the SQL table to use for the dict_map_field.

dict_map_field_pattern

Default	[None]
Value	string
See Also	dict_map_pattern dict_map_field

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

dict_map_field_type

Default	string
Value	string
Allowed Values	stringintuintdoublehexblobuuid
See Also	dict_map_field

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

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

Default	[None]
Value	Named List Filter
See Also	dict_map_value_name

• sql: Creates a new value for the dict map. The filter name refers to the dict_map_value_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_name

Default	[None]
Value	string
See Also	dict_map_value

Field in the SQL table to use for the dict_map_value.

dict_map_value_type

Default	string
Value	string
Allowed Values	stringintuintdoublehexblobuuid
See Also	dict_map_value

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

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

Default	[None]
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
    # ...
  }
}

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

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

The setting ALL allows all commands.

doveadm_api_key

Default	[None]
Value	string

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

If set, the key must be included in the HTTP request (via X-API-Key header) base64 encoded.

doveadm_password

Default	[None]
Value	string

The doveadm client and server must have a shared secret. This setting configures the doveadm server's password, used for client authentication.

Because it grants access to users' mailboxes, it must be kept secret.

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

Default	[None]
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.

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	[None]
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	[None]
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	[None]
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.

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	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	boolean
See Also	fts_autoindex_max_recent_msgs
Plugin	fts plugin

If enabled, index mail as it is delivered or appended.

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	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.

See the decode2text.sh script included in Dovecot for how to use this.

Example:

fts_decoder_driver = script
fts_decoder_script_socket_path = decode2text

service decode2text {
  executable = script /usr/lib/dovecot/decode2text.sh
  user = vmail
  unix_listener decode2text {
	mode = 0666
  }
}

fts_decoder_tika_url

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

Maximum body size that is processed by fts. 0 means unlimited.

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	[None]
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	[None]
Value	unsigned integer
Changes	Added: 2.4.0

Maximum number of parallel connections per peer.

http_client_max_pipelined_requests

Default	[None]
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	string
Changes	Added: 2.4.0

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	unsigned integer
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	[None]
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	[None]
Value	unsigned integer

Maximum number of pipelined requests per connection.

http_server_rawlog_dir

Default	[None]
Value	string

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_hibernate_timeout

Default	[None]
Value	time

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	[None]
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	[None]
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.

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.

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

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	[None]
Value	Port Number

The port on the remote IMAP host to connect to.

imapc_rawlog_dir

Default	[None]
Value	string
See Also	rawlog

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
}

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

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}
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_address

Default	[None]
Value	IP addresses

Overrides the listen setting for this listener.

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_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

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.

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.

TIP

For better performance it's recommended to synchronize this setting with the textcat configuration file; see textcat_config_path.

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; [\x20] Remove
Value	string
Plugin	fts plugin

Description of the normalizing/transliterating rules to use.

See Normalizer Format for syntax.

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:

• Apache Lucene,
• Snowball stemmer, or
• GitHub - Stopwords ISO.

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	[None]
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	[None]
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_generic_algorithm = tr29 and
• language_tokenizer_generic_wb5a = yes.

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	[None]
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

Default	[None]
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_key

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

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

last_login_precision

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

Precision for last login timestamp.

last_valid_gid

Default	[None]
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.

0 means there is no explicit last GID.

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

last_valid_uid

Default	[None]
Value	unsigned integer
See Also	first_valid_uid

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

0 means there is no explicit last UID.

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	no
Value	boolean
Plugin	lazy-expunge plugin

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	[None]
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.

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.

Example: ldap_base = dc=mail, dc=example, dc=org

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	0
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	*, ::
Value	IP addresses

A comma-separated 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

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	[None]
Value	unsigned integer

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.

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.

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.

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.

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	unsigned integer

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	[None]
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/.

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_socket_path

Default	[None]
Value	string
Changes	Added: 2.4.0

Default socket path for all services' login processes. Can be overridden by passing a parameter to the login executable.

login_source_ips

Default	[None]
Value	IP addresses

Value Format: List of trusted network ranges, see 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	IP addresses

Value Format: List of trusted network ranges, see Boolean List.

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})

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})

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

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)

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

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

• mail-lua plugin,
• push-notification-lua plugin, and
• Lua authentication database.

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	[None]
Value	Boolean List

Supplementary groups that are granted access for mail processes.

Typically, these are used to set up access to shared mailboxes.

WARNING

It may be dangerous to set these up if users can create symlinks.

Examples for if the "mail" group is chosen here:

• 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	string
See Also	dbox alternate storage

Specifies the dbox alternate storage path.

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	[None]
Value	Boolean List

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

Default	[None]
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
Value	Boolean List
See Also	mail_always_cache_fields mail_never_cache_fields

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	string

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_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	string

Location for (mailbox-format specific) control files.

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

Default	[None]
Value	Named Filter
See Also	fs_driver mail_ext_attachment_dir

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_dir

Default	[None]
Value	string

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 can be used.

mail_ext_attachment_min_size

Default	128k
Value	size
See Also	mail_ext_attachment_dir

Attachments below this size will not be saved externally.

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 numeric IDs or group names.

If you use multiple values here, userdb can override them by returning the gid field.

mail_home

Default	[None]
Value	string
See Also	mail_path quick configuration

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	string
See Also	mail_path

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

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_index_path

Default	<same as mail_path setting>
Value	string
See Also	Mail Index File Format Mail Location: Index Files

Location of Mail Index File Format.

mail_index_private_path

Default	[None]
Value	string
See Also	public shared mailboxes

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

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

Default	[None]
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_fsync

When mail-index files exist in NFS storage and you're running a multi-server setup that you wish to flush NFS caches, this can be set to yes (in this case, make sure also to use mmap_disable = yes and mail_fsync = optimized).

mail_nfs_storage

Default	no
Value	boolean

Flush NFS caches whenever it is necessary to do so.

This setting should only be enabled if you are using multiple servers on NFS.

mail_path

Default	<specific to mail_driver setting>
Value	string
See Also	Mail User Variables Home Directories for Virtual Users mail_driver

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_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	0
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

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

Typically, this is set to mail to give access to /var/mail.

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	[None]
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. If you use multiple values here, userdb can override them by returning UID or GID fields. You can use either numeric IDs or usernames here.

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	string

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.

mail_vsize_bg_after_count

Default	[None]
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.

TIP

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

mailbox "Test Mailbox" {
  # ...
}

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.

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

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	[None] 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).

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	[None] 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
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.

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	[None]
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.

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.

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 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	[None]
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	[None]
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 {
  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

Default	[None]
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

Default	[None]
Value	Named Filter
See Also	dict

A dictionary for fetching validation keys.

Example:

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_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_args

Default	[None]
Value	string

Arguments for the passdb driver. The format of this value depends on the passdb driver. Each one uses different args.

passdb_default_password_scheme

Default	PLAIN specific passdb have different defaults
Value	string

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

The driver used for this password database. If empty, defaults to passdb_name. See passdb for the list of available drivers.

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.

Note that you can't use any passdb_fields declaration if you use this setting.

Example: passdb_ldap_bind_userdn = cn=%{user},ou=people,o=org

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	[None]
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

SQL query to lookup the passdb fields (password and other extra fields).

passdb_sql_update_query

Default	[None]
Value	string

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.

passdb_username_filter

Default	[None]
Value	string
Changes	Added: 2.2.30

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.

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	[None]
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	[None]
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	string
See Also	rawlog

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 > 10M"

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

Default	[None]
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).

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

Default	[None]
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	unsigned integer
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	string
See Also	rawlog

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	[None]
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

Secondary UNIX groups that this process belongs to.

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
Changes	Changed: 2.3.21 This behavior was redesigned to work better in busy servers.

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.

service_process_min_avail

Default	[None]
Value	unsigned integer
See Also	service_client_limit service_restart_request_count service_process_min_avail

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 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_type

Default	[None]
Value	string
See Also	service_process_limit

Type of this service:

Value	Description
<empty>	The default.
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

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_forbid_add

Default	[None]
Value	string
See Also	Sieve editheader extension
Plugin	sieve plugin

A space-separated list of headers that cannot be added 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	[None]
Value	string
See Also	Sieve editheader extension
Plugin	sieve plugin

A space-separated list of headers that cannot be deleted 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, adding one of these headers to this setting has no effect.

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	String 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_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	String 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	[None]
Value	unsigned integer
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.

sieve_max_cpu_time

Default	30s
Value	time
Plugin	sieve plugin

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 for a single script execution, but also cumulatively for the last executions within a configurable timeout (see sieve_resource_usage_timeout).

sieve_max_redirects

Default	[None]
Value	unsigned integer
Plugin	sieve plugin

The maximum number of redirect actions that can be performed during a single script execution.

0 means redirect is prohibited.

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	String 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	[None]
Value	unsigned integer
Plugin	sieve plugin

The maximum number of personal Sieve scripts a single user can have.

Default is 0, which is unlimited.

sieve_quota_storage_size

Default	[None]
Value	unsigned integer
Plugin	sieve plugin

The maximum amount of disk storage a single user's scripts may occupy.

Default is 0, which is unlimited.

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
Plugin	sieve plugin

To prevent abuse, the Sieve interpreter can record resource usage of a Sieve script execution in the compiled binary if it is significant. Currently, this happens when CPU system + user time exceeds 1.5 seconds for one execution. Such high resource usage is summed over time in the binary and once that cumulative resource usage exceeds the limits (sieve_max_cpu_time), the Sieve script is disabled in the binary for future execution, 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 resource usage in the binary is reset. This means that the Sieve script is only disabled when the limits are cumulatively exceeded within this timeout. With the default configuration this means that the Sieve script is only disabled when the total CPU time of Sieve executions that lasted more than 1.5 seconds exceeds 30 seconds in the last hour.

A disabled Sieve script can be reactivated by the user by uploading a new version of the Sieve script after the excessive resource usage times out. An administrator can force reactivation by forcing a script compile (e.g. using the sievec command line tool).

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	String 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".

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

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_receipt

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> ]

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_virustest_score_max_value.

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.

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_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.

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_virustest_text_value).

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.

ssl

Default	yes
Value	string
Allowed Values	yesnorequired
See Also	SSL configuration

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 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.

This setting affects the secured state of connections. See secured connections.

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

Default	[None]
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 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.

ssl_client_ca_file

Default	[None]
Value	File
See Also	ssl 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.

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.

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_server

Default	[None]
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	boolean
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.

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

Default	[None]
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	[None]
Value	unsigned integer

Maximum number of recipients accepted per connection.

0 means unlimited.

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	[None]
Value	Port Number

Port for the submission relay server.

submission_relay_rawlog_dir

Default	[None]
Value	string
See Also	rawlog

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
Plugin	fts plugin

Path to the textcat/exttextcat configuration file, which lists the supported languages.

This is recommended to be changed to point to a minimal version of a configuration that supports only the languages listed in language.

Doing this improves language detection performance during indexing and also makes the detection more accurate.

Example:

textcat_config_path = /usr/share/libexttextcat/fpdb.conf

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_args

Default	[None]
Value	string

Arguments for the userdb driver. The format of this value depends on the userdb driver. Each one uses different args.

userdb_driver

Default	[None]
Value	string
See Also	userdb_name userdb

The driver used for this user database. If empty, defaults to userdb_name. See userdb for the list of available drivers.

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_attrs {
    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_attrs {
    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

SQL query to list all available usernames.

userdb_sql_query

Default	[None]
Value	string

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.

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

Default	[None]
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
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_policy_hash_truncate

Default	[None]
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_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.

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	[None]
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_max_term_size

Default	[None]
Value	unsigned integer
Plugin	fts-flatcurve plugin
Advanced Setting; this should not normally be changed.

The maximum number of characters in a term to index.

The maximum value for this setting is 200.

fts_flatcurve_min_term_size

Default	[None]
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_limit

Default	[None]
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	[None]
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_client_socket_path

Default	dns-client
Value	string
Changes	Added: 2.4.0
Advanced Setting; this should not normally be changed.

UNIX socket path to the dns-client service.

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	[None]
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	[None]
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_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 Variables can be used.

mail_cache_max_header_name_length

Default	[None]
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 disable with explicitly with mail_cache_max_header_name_length = 0)

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	[None]
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	[None]
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	[None]
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	[None]
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_dir
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	[None]
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	[None]
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.

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).

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	[None]
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	[None]
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	[None]
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_variables_max_scope_count

Default	[None]
Value	unsigned integer
See Also	Sieve vacation 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.

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	[None]
Value	unsigned integer
Plugin	virtual plugin
Advanced Setting; this should not normally be changed.

How many mailboxes to open in virtual plugin.