Can't send mail to some external addresses...

[glang]

My Zimbra server is setup and running great except for the fact that I can no longer send to some external addresses. For example I can send to my server hosted on supremecluster, but I can't send to gmail.com, yahoo.com, or msn.com. I've searched the web and the forums for some type of solution, but nothing is working. I have attempting setting up CNAME and PTR records in DNS as well as SPF records, and modifying the firewall but nothing changes the outcome. Below are the logs I am receiving; any ideas?

------------ Logs ------------
Aug 14 11:45:41 servername postfix/smtp[17423]: connect to gmail.com[74.125.127.83]: Connection timed out (port 25)
Aug 14 11:45:41 servername postfix/smtp[17419]: connect to gmail.com[74.125.79.83]: Connection timed out (port 25)
Aug 14 11:45:41 servername postfix/smtp[17422]: connect to gmail.com[209.85.225.83]: Connection timed out (port 25)
Aug 14 11:45:41 servername postfix/smtp[17424]: connect to gmail.com[209.85.225.83]: Connection timed out (port 25)
Aug 14 11:45:41 servername postfix/smtp[17425]: connect to gmail.com[74.125.79.83]: Connection timed out (port 25)
Aug 14 11:45:41 servername postfix/smtp[17419]: 1B35667CA4: to=, relay=none, delay=246750, delays=246660/0.02/90/0, dsn=4.4.1, status=deferred (connect to gmail.com[74.125.79.83]: Connection timed out)
Aug 14 11:45:41 servername postfix/smtp[17423]: D740967CA5: to=, relay=none, delay=240224, delays=240133/0.03/90/0, dsn=4.4.1, status=deferred (connect to gmail.com[74.125.127.83]: Connection timed out)
Aug 14 11:45:41 servername postfix/smtp[17422]: 1757967CD7: to=, relay=none, delay=3397, delays=3307/0.02/90/0, dsn=4.4.1, status=deferred (connect to gmail.com[209.85.225.83]: Connection timed out)
Aug 14 11:45:41 servername postfix/smtp[17424]: B6C9967CB3: to=, relay=none, delay=141523, delays=141432/0.03/90/0, dsn=4.4.1, status=deferred (connect to gmail.com[209.85.225.83]: Connection timed out)
Aug 14 11:45:41 servername postfix/smtp[17425]: 8197367CD8: to=, relay=none, delay=3387, delays=3297/0.04/90/0, dsn=4.4.1, status=deferred (connect to gmail.com[74.125.79.83]: Connection timed out)
Aug 14 11:45:41 servername postfix/qmgr[17766]: warning: connect to transport retry: Connection refused
Aug 14 11:45:41 servername postfix/qmgr[17766]: 63C9367CC0: to=, relay=none, delay=78572, delays=78482/90/0/0, dsn=4.3.0, status=deferred (mail transport unavailable)
------------ Logs ------------

[glang]

Ok, so I fixed the problem by turning on DNS lookups. Unfortunately, when I did that, and old problem returned where I receive the error "mail for bnesystems.com loops back to myself" when I send mail from username@server.domain.com to username@domain.com.

[dwmtractor]

Originally Posted by glang

Ok, so I fixed the problem by turning on DNS lookups. Unfortunately, when I did that, and old problem returned where I receive the error "mail for bnesystems.com loops back to myself" when I send mail from username@server.domain.com to username@domain.com.

I'm a little confused what you're trying to do here. username@server.domain.com and username@domain.com are functionally identical. I understand from your other thread that they're actually different servers, but I think what you are dealing with here is a built-in problem. Domains are supposed to be unique identifiers. Trying to have separate email systems that don't mix, on the same domain is asking for trouble and I'm not entirely sure you can ever hope to get it right.

Why not consider registering the .net version of your .com domain, and then having (for example) the corp server on the .net domain and the Network Solutions one on the .com?

Otherwise, I think every problem you fix is likely to pop up a different problem

The only other alternative I can think of would be to follow the instructions in the Split Domain wiki (which is designed for server migration--some users on Zimbra while others are on your previous mail server), but you've already rejected that idea on your other thread...