This documentation is for Dovecot v2.x, see wiki1 for v1.x documentation.

SQL

SQL can be used for both passdb and userdb lookups. If the args parameter in passdb sql and userdb sql contain the exact same filename, only one SQL connection is used for both passdb and userdb lookups.

Password database lookups

password_query setting contains the SQL query to look up the password. It must return a field named "password". If you have it by any other name in the database, you can use the SQL's "AS" keyword (SELECT pw AS password ..). You can use all the normal variables such as %u in the SQL query.

If all the passwords are in same format, you can use default_pass_scheme to specify it. Otherwise each password needs to be prefixed with "{password-scheme}", for example "{plain}plaintext-password". See Authentication/PasswordSchemes for a list of supported password schemes.

By default MySQL does case-insensitive string comparisons, so you may have a problem if your users are logging with different as "user", "User" and "uSer". To fix this, you can make the SQL database return a "user" field, which makes Dovecot modify the username to the returned value. Note that if you're using separate user and domain fields, a common problem is that you're returning only the "user" field from the database. This drops out the domain from the username. So make sure you're returning a concatenated user@domain string or username/domain fields separately. See the examples below.

The query can also return other extra fields which have special meaning.

You can't use multiple statements in one query, but you could use a stored procedure. If you want something like a last login update, use PostLoginScripting instead.

Password verification by SQL server

If the passwords are in some special format in the SQL server that Dovecot doesn't recognize, it's still possible to use them. Change the SQL query to return NULL as the password and return the row only if the password matches. You'll also need to return a non-NULL "nopassword" field. The password is in %w variable. For example:

password_query = SELECT NULL AS password, 'Y' as nopassword, userid AS user \
  FROM users WHERE userid = '%u' AND mysql_pass = password('%w')

This of course makes the verbose logging a bit wrong, since password mismatches are also logged as "unknown user".

User database lookups

Usually your SQL database contains also the userdb information. This means user's UID, GID and home directory. If you're using only static UID and GID, and your home directory can be specified with a template, you could use static userdb instead. It is also a bit faster since it avoids doing the userdb SQL query.

user_query setting contains the SQL query to look up the userdb information. The commonly returned userdb fields are uid, gid, home and mail. See UserDatabase/ExtraFields for more information about these and other fields that can be returned.

If you're using a single UID and GID for all users, you can set them in dovecot.conf with:

mail_uid = vmail
mail_gid = vmail

User iteration

Some commands, such as doveadm -A need to get a list of users. With SQL userdb this is done with iterate_query setting. You can either return

Any other fields are ignored.

Prefetching

If you want to avoid doing two SQL queries when logging in with IMAP/POP3, you can make the password_query return all the necessary userdb fields and use prefetch userdb to use those fields. If you're using Dovecot's deliver you'll still need to have the user_query working.

See UserDatabase/Prefetch for example configuration

High availability

You can add multiple "host" parameters to the SQL connect string. Dovecot will do round robin load balancing between them. If one of them goes down, the others will handle the traffic.

Examples

Note that "user" can have a special meaning in some SQL databases, so we're using "userid" instead.

SQL table creation command:

CREATE TABLE users (
    userid VARCHAR(128) NOT NULL,
    domain VARCHAR(128) NOT NULL,
    password VARCHAR(64) NOT NULL,
    home VARCHAR(255) NOT NULL,
    uid INTEGER NOT NULL,
    gid INTEGER NOT NULL
);

MySQL

Add to your dovecot-sql.conf file:

driver = mysql
# The mysqld.sock socket may be in different locations in different systems.
# Use "host= ... pass=foo#bar" with double-quotes if your password has '#' character.
connect = host=/var/run/mysqld/mysqld.sock dbname=mails user=admin password=pass
# Alternatively you can connect to localhost as well:
#connect = host=localhost dbname=mails user=admin password=pass

password_query = SELECT userid AS username, domain, password \
  FROM users WHERE userid = '%n' AND domain = '%d'
user_query = SELECT home, uid, gid FROM users WHERE userid = '%n' AND domain = '%d'

# For using doveadm -A:
iterate_query = SELECT userid AS username, domain FROM users

PostgreSQL

Add to your dovecot-sql.conf file:

# You can also set up non-password authentication by modifying PostgreSQL's pg_hba.conf
driver = pgsql
# Use "host= ... pass=foo#bar" if your password has '#' character
connect = host=localhost dbname=mails user=admin password=pass

password_query = SELECT userid AS username, domain, password \
  FROM users WHERE userid = '%n' AND domain = '%d'
user_query = SELECT home, uid, gid FROM users WHERE userid = '%n' AND domain = '%d'

# For using doveadm -A:
iterate_query = SELECT userid AS username, domain FROM users

SQLite

Add to your dovecot-sql.conf file:

driver = sqlite
connect = /path/to/sqlite.db

password_query = SELECT userid AS username, domain, password \
  FROM users WHERE userid = '%n' AND domain = '%d'
user_query = SELECT home, uid, gid FROM users WHERE userid = '%n' AND domain = '%d'

# For using doveadm -A:
iterate_query = SELECT userid AS username, domain FROM users

PostgreSQL/Horde

I used the following in devocot-sql.conf file to authenticate directly against the Horde user/password database (with static userdb) on PostgreSQL:

driver = pgsql
connect = host=localhost dbname=horde user=dovecot password=
default_pass_scheme = MD5-CRYPT
password_query = SELECT user_uid AS username, user_pass AS password \
   FROM horde_users WHERE user_uid = '%u'
iterate_query = SELECT user_uid AS username FROM users

Note that you will have to change the password encryption in Horde to MD5-CRYPT. Also, the example above requires a 'dovecot' user in PostgreSQL with read (SELECT) privileges on the 'horde_users' table.

AuthDatabase/SQL (last edited 2013-06-21 20:50:30 by TimoSirainen)