This is continuing my thread here - http://www.zimbra.com/forums/showthread.php?t=2085 - a few weeks back.
I successfully allowed relay from one particular ip and it is working for the user. Every time the user sends an email (any domain, gmail, yahoo, etc) it successfully gets delivered to the intended recipient.
However, with every message sent, the user gets this message returned to him.
Subject: Undelivered Mail Returned to Sender
This is the Postfix program at host cmsfwd02.mx.net.
I'm sorry to have to inform you that your message could not be be delivered to one or more recipients. It's attached below.
The Postfix program
<email@example.com>: host mx.usa.net[18.104.22.168] said:
Too many hops 33 (30 max) (in reply to end of DATA command)
None of the hosts listed here is my host. Can anyone shed some light on this for me? Thank you.