Transport Table for external servers

Configuring transport tables to relay all emails to an different mail server. In this example I am forwarding all emails for otherdomain.com to smtp.otherdomain.com . You can add many transport maps as per your need. All commands should be run as Zimbra.

$ zmlocalconfig   |grep -i postfix_transport_maps

This will show you current transport maps file configuration.

Create your transport file (owner/group-owner should be zimbra). You can also add multiple transport maps.

vi /opt/zimbra/postfix/conf/transportfile
otherdomain.com     :[smtp.otherdomain.com]

Define new transport file instead of the default one.

$ zmlocalconfig -e postfix_transport_maps=hash:/opt/zimbra/postfix/conf/yourtransportfile,ldap:/opt/zimbra/conf/ldap-transport.cf

Convert the transport file into maptype database file.

$ postmap /opt/zimbra/postfix/conf/transportfile

Restart Zimbra

zmcontrol stop
zmcontrol start

This will forward all emails for otherdomain.com and its subdomains to host smtp.otherdomain.com However you'll need to be careful at zimbra upgrades. The modification will be overwritten by the upgrade. If you still not able to set the correct transport tables, contact Zimbra Support.