Well, from that information it's clear you don't have the same problem as the original poster. What you've probably got is an incorrect /etc/hosts file and no valid DNS A & MX records - they are needed. I assume you're running behind a NAT router and your Zimbra server has a fixed IP address?
Please post the output of the following commands (run on your Zimbra server):
Code:
cat /etc/hosts
cat /etc/resolv.conf
dig yourdomain.com mx
dig yourdomain.com any
host `hostname` <-- type that command exactly using backticks not single quotes
When you post the output of each command highlight the text and surround it with 'quotes' (hit the # symbol above the edit box) to make it easier to read.
I'd also suggest you read the
Quick Start Installation Guide for the format of the /etc/hosts file then read this
wiki article on setting up a Split DNS.