I have followed the steps in the wiki as shown here
Restrict users to certain domain - Zimbra :: Wiki several times now and when I get to the end of the settings and do zmmtactl start, the mta does a couple of things and then gives me about 8 warnings about files that are not owned by root and 6 more warnings about files not owned by zimbra. In order to edit the files postfix_recipient_restrictions.cf and zmmta.cf as the 'zimbra' user, I had to do chmod on those as sudo (running Ubuntu 8.04 LTS) and then su - zimbra to have permissions to change those files.
What am I missing? Sorry I am relatively new to Linux but am loving working with it. I followed the above mentioned wiki entry exactly (as best I could with the mentioned permissions problem) and it totally breaks all email sending on zimbra. I can't send any mail from any account to any account after doing that.
Thanks for any info.