I’ve been doing a bit of work on Mandriva recently, and I always forget that there are two places you need to change the host name before it “takes”.

in /etc/sysconfig/network add the following line:

HOSTNAME=hostname

Where hostname is whatever you want the computer to be called.

Then in /etc/hosts just add the hostname after localhost on the first (and probably only) line in the file. It should look something like:

127.0.0.1       hostname localhost

Where again hostname is the name of the computer.

Do this, reboot, and all should be well.