My CentOS 5.6 server's hostname was "centos" . And then i change it to my domain :

hostname domain.com

And i started to installing WHM / cPanel as explained in here : http://etwiki.cpanel.net/twiki/bin/view/AllDocumentation/InstallationGuide/InstallingCpanel

It's installed very well. And the i reboot my server.

After rebooting, i was execute this command for open WHM's 2087 port :

iptables -I RH-Firewall-1-INPUT -m state --state NEW -m tcp -p tcp --dport 2087 -j ACCEPT

Now i'm trying to browse domain.com:2087 i'm getting Server (centos) not found .I noticed it's forwarding to my old hostname (centos) . And then execute this command to verify me hostname

hostname

it's returned "centos" again. I'm not sure, why it's returned to old hostname. (I think it returned to old hostname after rebooting) . I'm changed it one more time :

hostname domain.com

Finally, now my hostname is domain.com . BUt still i'm getting centos server not found error.

This is result of iptables -L command.

P.S. : domain.com/cpanel is working