Change the Hostname (RHEL5)

To change the hostname of a Red Hat Enterprise Linux 5 system (Might work on v6 but is untested)

Change the contents of the file /etc/sysconfig/network:

NETWORKING=yes
NETWORKING_IPV6=no
HOSTNAME=sbultra-136100027

Then reboot the system. 

To make the change without rebooting you can use the hostname command but upon reboot (if the aforementioned file is not updated) the change will not persist.

hostname NEW_HOSTNAME

ex: hostname server1