I've got Zimbra installed inside my firewall for internal users. This all works great.
Historically we have MDaemon as our edge MTA, but it keeps getting a huge amount of undeliverable email set to it. If it could refuse emails to unknown emails, the traffic would reduce massively.
It can do email account checking (LDAP) via its domain connector, but I just can't seem to get it to talk to my Zimbra server. I think I have opened up the correct ports on the firewall (TCP & UDP 389). I'm also uncertain of the required security to pass.
Can anyone help?