Are you asking how to create a DNS server so that other machines can use yours for resolving names or are you just asking how to allow yours to resolv names from an existing DNS server?
The latter is fairly simple.
Just edit /etc/resolv.conf and add entries for your nameserver(s):
Where xxx.xxx.xxx.xxx is the IP address of the name server.
If you have more than one name server you just add another line below the first one using the same format.
Also if this is an internal LAN (say at your office) where most hosts have the samin domain you can add a search string at the beginning of the file:
search domain1.com domain2.net dmz.domain1.com
The above would let you just type "host" or "dig" followed by a host name without requiring the Fully Qualified Domain Name (FQDN).
is an FQDN where "google.com" is a domain.
Say you had a host with an FQDN of somehost.dmz.domain1.com. Without the search string you have to type:
With the search string you only have to type:
as it will try somehost.domain1.com then somehost.domain2.net then somehosts.dmz.domain1.com.
P.S. Verify your /etc/nsswitch.conf file has a line like:
hosts: files dns
This line tells it to lookup hosts first in your local /etc/hosts file and THEN dns. You don't have to put it in this order but most people do. The important thing is to have "dns" in there otherwise it won't use /etc/resolv.conf.