We pick h.root-servers.net, one of the 13 root servers (1), and ask it about yahoo.ua and learn that ua is delegated to six name servers (2), so we ask he1.ns.ua where we learn that yahoo.ua is delegated to five name servers, including ns2.yahoo.com (3), so we ask that one and get the following answer:
Yahoo.ua is a domain controlled by four domain name servers at yahoo.com. All four of them are on different IP networks. Incoming mail for yahoo.ua is handled by one mail server at .. We are missing the IP:s of one server: .. Yahoo.ua has two IP numbers (184.108.40.206, 220.127.116.11). Both are on different IP networks.
The five name servers ns1, ns2, ns3, ns4 and ns5.yahoo.com together
Two thirds of the several thousand of domains that use name server group 1 point to IP group 1 (example: smallbusinessyahoo.dk, av.com and yahooboy4.com ). Worth noting is that most of the host names that point to IP group 1 use name server group 1.
The name server ns1.yahoo.com
There are several thousand of domains that use the name server ns1.yahoo.com.