You should have a look at the Zimbra Quick Start Guide or search the forums, this has been covered many times.
The /etc/hosts file should be:
Code:
127.0.0.1 localhost.localdomain localhost
192.168.x.x name.yourdomain.com name
Obviously substitute your servers LAN IP for 192.168.x.x and 'name.yourdomain.com' should be the FQDN of your Zimbra server and you need DNS A & MX records pointing to it.