I've been struggling to get this working, so now I'll post my situation. We migrated our ~30 users to Zimbra from a sendmail/dovecot setup a couple months ago. Everything has been smooth, and now I'm trying to hammer out some small issues.
1) Before the switch, we had a "generic" table that mapped email@example.com to JohnDoe@MyCompany.Com. The generic table mapped johndoe to JohnDoe, and a "myorigin" directive did the MyCompany.com. It worked fine. Since the switch to Zimbra, I've been able to set this up on our Postfix edge MTA just fine, so all mail destined for external delivery gets translated OK. But I cannot seem to get it to work for internal addresses -- it always bounces. What I tried was modifying zmmta.cf to include:
I then placed the generic map in /opt/zimbra/postfix/conf and ran postmap generic. No love... I'm stuck. Does anyone know how to get this working? Or can I just force even internal mail to go the the edge MTA first?
POSTCONF generic_maps LOCAL postfix_generic_maps
2) OR... can you just force your alias, not your username, to appear in the "From" field on internal emails?
Thanks. And we love Zimbra!!!