Postfix doesn't support LDAP lookup tables

Solution Unverified - Updated -

Environment

  • Red Hat Enterprise Linux (RHEL) 8.0
  • postfix-3.3.1-8.el8_0_0

Issue

Postfix ignores LDAP directives and doesn't support LDAP lookup tables.

This can manifests by the /var/log/maillog snips similar to the following:

Feb 28 13:11:41 host-01 postfix[1886]: /usr/sbin/postconf: warning: ldap:/etc/postfix/ldap-aliases.cf: unused parameter: server_host=example.com:1234
Feb 28 13:11:41 host-01 postfix[1886]: /usr/sbin/postconf: warning: ldap:/etc/postfix/ldap-aliases.cf: unused parameter: result_attribute=rfc822MailMember
Feb 28 13:11:41 host-01 postfix[1886]: /usr/sbin/postconf: warning: ldap:/etc/postfix/ldap-aliases.cf: unused parameter: search_base=dc=example, dc=com
Feb 28 13:11:41 host-01 postfix[1886]: /usr/sbin/postconf: warning: ldap:/etc/postfix/ldap-aliases.cf: unused parameter: bind=no
Feb 28 13:11:41 host-01 postfix/master[1961]: daemon started -- version 3.3.1, configuration /etc/postfix
Feb 28 13:11:41 host-01 systemd[1]: Started Postfix Mail Transport Agent.

Resolution

The postfix-ldap package is required for LDAP lookup tables to work. The postfix-ldap package is not yet shipped in RHEL 8 and the issue is tracked by Bug 1686721

For more details and updates please contact Red Hat Support.

Root Cause

Postfix upstream added support for dynamic loading of lookup table types (sometimes called dynamic maps support) which allows loading of multiple lookup table types support at run-time. This allows lowering the number of link dependencies of the main postfix package and split it to multiple sub-packages containing so called plugins supporting individual lookup table types. In RHEL 8 the postfix package has been rebased and splitted to support this feature. Thus, if support for specific lookup table type is needed, the corresponding sub-package has to be installed.

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