I've already posted this question but have not received an answer so sorry for posting again, we are desperate.
We really need to have exim and postfix running on the same machine. We have configured postfix/zimbra mta to run on port 26, exim on port 25. Exim receives on port 25 and sends mail out to port 26 where postfix picks it up and delivers it successfully to the zimbra store. Zimbra sends mail to other zimbra users fine. But when we try to send mail from zimbra to an external domain we get "mail loops back to myself" error. Our outgoing mail server settings in zimbra can be either 127.0.0.1:25, 10.0.0.1:25 (the servers main IP address) or any IP alias we create but postfix always refuses to deliver even though we are delivering to another port (25).
Is there anyway we can configure postfix to send mail back to our own machine and stop the looping error message?