Q:

can't ping myself after I changed hostname

I've changed my hostname in etc/hostname from ubuntu to ubuntuclient but now I can't ping myself. as a result I always get unknown host: ubuntuclient.guf.by. What is wrong?

A:

Don't forget to change the hostname in the /etc/hosts file as well.
http://www.liberiangeek.net/2011/03/change-hostname-computer-name-ubuntu-11-04-natty/

