Ubuntu: set domain name

Temporarily:

domain <domain name>

Permanently:

change /etc/hosts:

127.0.0.1 cow02.LINUX-NIS 192.168.0.102 cow02.LINUX-NIS

check with hostname -d, you will see domainname

However, using 'domainname' still not work.

Further change /etc/sysctl.conf:

kernel.domainname = LINUX-NIS

Then, sysctl -p to update

You will see domainname works.