You need to run DNS servers (at least two). I'd suggest buying a book entitled, DNS and BIND published by O'Reilly... If you don't want to run your own, you can have your ISP or someone else do the DNS for your domain as well. They usually charge about $5-10/month to do that, so you might wanna run your own DNS servers. I'd look for some site's that specialize in that but I can't right now... If you need some, lemme know and I'll look... Cheers!