LDAP Backend Configuration

The included dovecot-ldap-backend.conf.ext can be used as template for the /etc/dovecot/dovecot-ldap.conf.ext. Its most important settings are:

hosts = ldap.example.com
dn = cn=admin,dc=example,dc=com
dnpass = secret
base = dc=example,dc=com

Configure how the LDAP server is reached.

auth_bind = yes

Use LDAP authentication binding for verifying users’ passwords.

blocking = yes

Use auth worker processes to perform LDAP lookups in order to use multiple concurrent LDAP connections. Otherwise only a single LDAP connection is used.

pass_attrs = \
=user=%{ldap:mailRoutingAddress}, \
=password=%{ldap:userPassword}, \

Normalize the username to exactly the mailRoutingAddress field’s value regardless of how the pass_filter found the user. The userdb_quota_rule is used by userdb prefetch to return the userdb values. If other userdb fields are wanted, they must be placed to both user_attrs (without userdb_ prefix) and pass_attrs (with userdb_ prefix).

user_attrs = \
=user=%{ldap:mailRoutingAddress}, \

Returns userdb fields when prefetch userdb wasn’t used (LMTP & doveadm). The username is again normalized in case user_filter found it via some other means.

pass_filter = (mailRoutingAddress=%u)
user_filter = (mailRoutingAddress=%u)

How to find the user for passdb lookup.

iterate_attrs = mailRoutingAddress=user
iterate_filter = (objectClass=smiMessageRecipient)

How to iterate through all the valid usernames.