We pick l.root-servers.net, one of the 13 root servers (1), and ask it about altavista.sc and learn that sc is delegated to seven name servers (2), so we ask b0.cctld.afilias-nst.org where we learn that altavista.sc is delegated to four name servers, including ns1.yahoo.com (3), so we ask that one and get the following answer:
Altavista.sc is a domain controlled by five domain name servers at yahoo.com. All five of them are on different IP networks. Incoming mail for altavista.sc is handled by one mail server at .. We are missing the IP:s of one server: .. Altavista.sc has two IP numbers (68.180.206.184, 98.139.102.145). Both are on different IP networks.
The five name servers ns1, ns2, ns3, ns4 and ns5.yahoo.com together
Three quarter of the more than hundred domains that use name server group 1 point to the two IP numbers 68.180.206.184 and 98.139.102.145 together, hereafter referred to as "IP group 1", (example: cgi2-yahoo.com, dlsyahoo.com and emailyahoomail.com ). Worth noting is that most of the host names that point to IP group 1 use name server group 1.
The mail server. Only
There are about sixty domains that only use the mail server ..