Zimbra Installation Pitfalls: It’s All About the Name

In the time that I spend over on the Zimbra forums, it seems that the biggest thing that causes new installations to fall flat on their faces and frustrate potential new users is name resolution. Most issues can be narrowed down to:

Incorrectly set hostname
During the installation of some distros, it’s easy to get the hostname messed up. Just running a ‘hostname -f’ before the installation to verify the name has been set can easily catch any issues that may come up later.

Incorrect /etc/hosts file
Zimbra is very sensitive to the values in your /etc/hosts file. Making sure that it is set correctly is very important for a successful installation. If your hostname is, say mail.thesysadminlog.com and the IP is 10.10.10.10, then your hosts file should look like:
127.0.0.1 localhost.localdomain localhost
10.10.10.10 mail.thesysadminlog.com mail


Missing, misconfigured, or misunderstanding of DNS
Another key component to a working Zimbra system is proper configuration of DNS for the server. There are a number of scenarios surrounding DNS configuration with Zimbra and plenty of help in the wiki and forums, but in general you need:

1. An A record in your DNS server pointed to the new Zimbra server’s real IP address. It doesn’t matter if this is a private, non-routable IP or a public IP. It simply needs to be an A record for the Zimbra server’s hostname that points to the real IP address of the network interface of the Zimbra server.
2. An MX record for the domain you want to use pointed at the A record you created. While this isn’t entirely necessary, it does make the install go a bit smoother.
3. Configure the Zimbra server to use the DNS server you just setup and no other. Of course, you can replicate to one or more name servers and add those to your /etc/resolv.conf file, but don’t add extra name servers to the list in /etc/resolv.conf.

Hopefully I’ve helped mitigate some of the pitfalls you may find yourself falling into during your Zimbra installation. For a more inclusive how-to, you can also check out my full Zimbra how-to. While it was written against Zimbra 5.0, the article should apply against 6.0 (I’ll be going through it soon to check for missing prerequisites