So I have to change the hostname on a server running Red Hat Enterprise Linux (v5). As I have to do this quite often I figured that I would note down where I need to change it.

• Update the HOSTNAME entry in /etc/sysconfig/network

• Update the entry in /etc/hosts to have the correct new hostnames both with domains and without.

• Update the list of hostnames that sendmail will accept emails for in /etc/mail/local-host-names.

• run hostname <NEW_HOSTNAME>

• This will update the hostname there and then, and avoids the need to restart the server to pick up the new hostname.

• Finally, if your server has DNS entries pointing to it update these to include the new hostname.