Update your Hostname

From LinodeWiki

[edit] Permanently

To permanently change the hostname of your linode, edit the /etc/sysconfig/network file and change the HOSTNAME=localhost.localdomain line to:

HOSTNAME=fully.qualified.hostname

(when does this take effect?)

[edit] Temporarily

To temporarily change the hostname of your linode, create a file name /etc/hostname using this command:

echo fully.qualified.hostname > /etc/hostname

To change the hostname at any time, issue the following command:

/bin/hostname -F /etc/hostname

After the /etc/hostname file is created once, the first step is not necessary unless one wishes to change the hostname. Changes to the hostname using this method will revert when the server is rebooted.