doveadm-pw¶

NAME¶

doveadm-pw - Dovecot’s password hash generator

SYNOPSIS¶

doveadm [GLOBAL OPTIONS] pw -l

doveadm [GLOBAL OPTIONS] pw [-p password] [-r rounds] [-s scheme] [-u user] [-V]

doveadm [GLOBAL OPTIONS] pw -t hash [-p password] [-u user]

DESCRIPTION¶

doveadm pw is used to generate password hashes for different password scheme s and optionally verify the generated hash.

All generated password hashes have a {scheme} prefix, for example {SHA512-CRYPT.HEX}. All passdbs have a default scheme for passwords stored without the {scheme} prefix. The default scheme can be overridden by storing the password with the scheme prefix.

In particular, if you want to use this to verify or generate passwords, without configuring Dovecot first, you can use doveadm -O pw to do so.

GLOBAL OPTIONS¶

Global doveadm(1) options:

-D: Enables verbosity and debug messages.
-O: Do not read any config file, just use defaults.
-k: Preserve entire environment for doveadm, not just import_environment.
-v: Enables verbosity, including progress counter.
-i instance-name: If using multiple Dovecot instances, choose the config file based on this instance name. See instance_name setting for more information.
-c config-file: Read configuration from the given config-file. By default it first reads config socket, and then falls back to /etc/dovecot/dovecot.conf. You can also point this to config socket of some instance running compatible version.
-o setting=value: Overrides the configuration setting from /etc/dovecot/dovecot.conf and from the userdb with the given value. In order to override multiple settings, the -o option may be specified multiple times.

OPTIONS¶

-l

List all supported password scheme s and exit successfully.

There are up to three optional password schemes: BLF-CRYPT (Blowfish crypt), SHA256-CRYPT and SHA512-CRYPT. Their availability depends on the system’s currently used libc.

-p password

The plain text password for which the hash should be generated. If no password was given doveadm(1) will prompt interactively for one.

-r rounds

The password scheme s BLF-CRYPT, SHA256-CRYPT and SHA512-CRYPT supports a variable number of encryption rounds. The following table shows the minimum/maximum number of encryption rounds per scheme. When the -r option was omitted the default number of encryption rounds will be applied.

 Scheme       | Minimum | Maximum   | Default
----------------------------------------------
 BLF-CRYPT    |       4 |        31 |       5
 SHA256-CRYPT |    1000 | 999999999 |    5000
 SHA512-CRYPT |    1000 | 999999999 |    5000

-s scheme

The password scheme which should be used to generate the hashed password. By default the CRYPT scheme will be used (with the $2y$ bcrypt format). It is also possible to append an encoding suffix to the scheme. Supported encoding suffixes are: .b64, .base64 and .hex.

See also https://doc.dovecot.org/configuration_manual/authentication/password_schemes/ for more details about password schemes.

-t hash

Test if the given password hash matches a given plain text password. You should enclose the password hash in single quotes, if it contains one or more dollar signs ($). The plain text password may be passed using the -p option. When no password was specified, doveadm(1) will prompt interactively for one.

-u user

When the DIGEST-MD5 scheme is used, also the user name must be given, because the user name is a part of the generated hash. For more information about Digest-MD5 please read also: https://doc.dovecot.org/configuration_manual/authentication/digest-md5/

-V

When this option is given, the hashed password will be internally verified. The result of the verification will be shown after the hashed password, enclosed in parenthesis.

EXAMPLE¶

The first password hash is a DIGEST-MD5 hash for jane.roe@example.com. The second password hash is a CRAM-MD5 hash for john.doe@example.com.

doveadm pw -s digest-md5 -u jane.roe@example.com
Enter new password:
Retype new password:
{DIGEST-MD5}9b9dcb4466233a9307bbc33708dffda0
doveadm pw
Enter new password:
Retype new password:
{CRAM-MD5}913331d8782236a8ecba7764a63aa27b26437fd40ca878d887f11d81245c2c6b

REPORTING BUGS¶

Report bugs, including doveconf -n output, to the Dovecot Mailing List <dovecot@dovecot.org>. Information about reporting bugs is available at: https://dovecot.org/bugreport.html