I've been messing with this one for days and was hoping someone can provide some incite. I have an internal Zimbra server running on the "domainname.com" domain. It is working perfectly and can send/receive email to/from anywhere without problems unless I try to send to the external "domainname.com" domain. For a more in-depth explanation:
I'm running split DNS for the "domainname.com" domain.
The server is "bluewhale.domainname.com" and the Zimbra domain is "corp.domainname.com". If I want to send to an internal user I send a mail to "email@example.com" and everything works fine. But, if I try to send to an external user at "firstname.lastname@example.org" I receive a message saying "
: mail for domainname.com loops back to myself".