We pick k.root-servers.net, one of the 13 root servers (1), and ask it about beta.sapo.pt and learn that pt is delegated to eight name servers (2), so we ask ns-pt.nlnetlabs.nl where we learn that sapo.pt is delegated to four name servers, including dns01.sapo.pt (3), so we ask that one and get the following answer:
Beta.sapo.pt is a domain controlled by two domain name servers at sapo.pt. Both are on the same IP network. Beta.sapo.pt has one IP number (213.13.146.140), which also has a corresponding reverse pointer.
Six of them point to the IP number 213.13.146.140. Worth noting is that six of the host names that point to the IP number 213.13.146.140 use the name server ns2.sapo.pt.
There are 13 host names that point to the IP number 213.13.146.140.
Ten of those point only to that ip number (example: www.sapo.ao ).
Six of them use the name server ns2.sapo.pt. Worth noting is that six of the domains that use the name server ns2.sapo.pt point to the IP number 213.13.146.140.
Six of them use the name server ns.sapo.pt. Worth noting is that six of the domains that use the name server ns.sapo.pt point to the IP number 213.13.146.140.