I have an ubuntu 6.06 server that I have installed zimbra on -- everything appears to be working (status in GUI and zmcontrol) but I cannot mail outside of my domain. Mail from my host, zim.sub.domain.edu to users in my domain, sub.domain.edu, works fine (and back). Mail from zim.sub.domain.edu to e.g. hotmail or gmail or yahoo breaks, and mail from outside in times out. I can telnet to an outside mx on port 25 and send mail via SMTP commands.
My domain is sub.domain.edu and I have setup my server to be zim.sub.domain.com. I do not want zimbra to handle mail for all my domain, just zim.sub.domain.com (ie, all my users to have
user@zim.sub.domain.com addresses). As such, I have not created MX records in my DNS for my domain, since mail to the machine will get routed correctly via regular DNS. sub.domain.com is my delegated domain from domain.edu, and zim.sub.domain.edu is a host in my domain (not a sub-domain in and of itself). I have other machines setup like this and they're working fine.
The only other thing I can think of is that my IP addressing is messing it up -- all my machines (including zim) are 172.16.x.x private addresses, and NAT'd/MIP'd at my firewall if they need a public IP. This machine /does/ have a public IP via Mapped IP (all internal records point to the private IP, all public records point to the public IP, FW does the translating from outside->in, inside->out.
Suggestions or thoughts?