I have some iPhone users who access my Zimbra server as a plain IMAP client (they don't want to be notified for each new message, they want pull messaging). They're a little old-school and would like to be able to send mail to the unqualified <username>, not just <username@my.happy.domain>. I poked around and found the postfix reject_non_fqdn_recipient, but I can't seem to make that go. I have configured:

$ zmprov gcf zimbraMtaRestriction
zimbraMtaRestriction: reject_invalid_hostname

Which used to contain an additional "zimbraMtaRestriction: reject_non_fqdn_recipient" specification, but after zmmtactl stop && zmmtactl start, I still see that reject_non_fqdn_recipient shows up in the postfix main.cf. Can anyone tell me the supported way to do this?

My Zimbra installation sits behind a router ACL protecting SMTP, and I have a spam/virus appliance, so I'm not worried about spammers, just relaying/delivering for my authenticated clients.