We pick f.root-servers.net, one of the 13 root servers (1), and ask it about bulgari.sm and learn that sm is delegated to four name servers (2), so we ask dns.omniway.sm where we learn that bulgari.sm is delegated to two name servers, including ns1.nice.net (3), so we ask that one and get the following answer:
Eleven percent of them point to the IP number 151.1.157.103. Worth noting is that half of the host names that point to the IP number 151.1.157.103 use the name server ns3.nice.net.
The IP number 151.1.157.103 only
A third of the more than hundred host names that point only to the IP number 151.1.157.103 use the three name servers ns1, ns2 and ns3.nice.net together (but not ns4.nice.net ), hereafter referred to as "name server group 2", (example: prixcmca.com, marinatevere.com and klosed.net ). Worth noting is that a third of the domains that use name server group 2 point only to the IP number 151.1.157.103.
The four name servers ns1, ns2, ns3 and ns4.nice.net together
There are several hundred of domains that use name server group 1.