I'm assuming that you're referring to running a DNS server yourself....

depends on what OS the host machine is running:

1. Windows - run the native DNS component.
2. *Nix - BIND

No cost associated with either choice other than your own time and energy. Here are respective links for each to get you going...

1. http://www.petri.co.il/install_and_c...dns_server.htm
2. www.google.com (there are so many variations, you should search specifically for your platform).


Note: You could also run BIND on Windows is so inclined.


Cheers,
<0