1. Use the hostname utility
hostname myservernamehereor, use a fully qualified hostname like
2. Alter the hostname in /etc/sysconfig/network
nano /etc/sysconfig/networkChange your old hostname by editing the text on the line after HOSTNAME=
3. Alter the hostname in /etc/hosts
nano /etc/hostsIf your old hostname is present here, edit it out and replace it with your new one.
4. Don't forget rDNS / Reverse DNS / PTR !
Ask your web host (that's probably us) to alter your PTR/rDNS record to the fully qualified domain name you changed your hostname to. If you did not use a fully qualified domain name and it is not resolvable in DNS, you will not be able to complete this step, and you may experience difficulties when sending or receiving e-mail to/from your server.