nameserver?
 

I am a little confused on how this is set up. I have noticed when you do a whois look up for facebook.com it displays ns1.facebook.com ns2.facebook.com
how is this possible. if you need the nameserver to look up the host of facebook.com inorder to find out where is ns1, ns2. can someone please explain how this is setup or suggest a forum where i can ask this. thank you

This is possible by using glue records. Please see wikipedia for a detailed explanation:

http://en.wikipedia.org/wiki/Domain_...d_glue_records