Adding multiple mail domains in LDAP

Intro

LDAP makes it a breeze to add multiple domain names you wish to serve email accounts with. Although I am describing how I configured multiple domains in my own environment using OpenLDAP - this should also work for other LDAP implementations.

Domains Organizational Unit

dn: ou=Domains,dc=domain1,dc=net
objectClass: organizationalUnit
objectClass: top
ou: Domains
description: Domains used for Postfix as its list of locally hosted domains

This LDIF will define our Domains Organizational Unit (OU). Add the LDIF with ldapadd so our domains have a container to live in.

Adding Domains

dn: dc=domain1.net,ou=Domains,dc=domain1,dc=net
dc: domain1.net
objectClass: dNSDomain
objectClass: top

dn: dc=domain2.me,ou=Domains,dc=domain1,dc=net
dc: domain2.me
objectClass: dNSDomain
objectClass: top

After importing our domains from an LDIF we can now verify our 2 domains in LDAP get returned with the postmap command.

$ postmap -q domain1.net ldap:/etc/postfix/ldap/ldap-virtual-domains.cf

domain1.net

$ postmap -q domain2.me ldap:/etc/postfix/ldap/ldap-virtual-domains.cf

domain2.me