DollarDNS | Whois Direct
Domain Name Server Registrar IP Address Advanced
Query:
   This is where you can query a registered name server if the whois server 
 supports name server queries.  Information can include the IP address and
 registrar of the name server.  Just enter the full domain of the name server
 you registered and press enter.

   Whois results may contain links you can click on for more information.

   Examples

     Query: ns1.dollardns.net
     Query: ns1.dollardns.org

   Additional Information

     There aren't many servers that support name server queries.  So far I only
   know COM/NET/EDU, ORG/INFO, and BIZ/US domains will work.  If I should find
   another server that supports name server queries, I will add support for it.