DNS Settings for Linux

File for client DNS resolution as well as the default domain search is: /etc/resolve.conf

Modify this file:
vi /etc/resolve.conf

to appear like:
search relevantads.com
nameserver 4.2.2.1
nameserver 4.2.2.4

No restart should be required.

You can replace the term "relevantads.com" with your local domain name. That will allow for pinging a machine without fully qualified domain name.

The nameserver records should ideally be provided by your ISP. The above 4.2... records are gold TLD's which may block abusive traffic.