We pick b.root-servers.net, one of the 13 root servers (1), and ask it about ns2.fm and learn that fm is delegated to six name servers (2), so we ask tld2.ultradns.net where we learn that ns2.fm is delegated to two name servers, including ns2.fm (3), so we ask that one and get the following answer:
Ns2.fm is a domain controlled by two domain name servers at ns2.fm and ns1.fm. Both are on the same IP network. Ns2.fm has one IP number (119.252.116.136), which also has a corresponding reverse pointer.
There are about sixty domains that use the name server ns2.fm.
Most of those use the two name servers ns1 and ns2.fm together, hereafter referred to as "name server group 1", (example: bofsm.fm, cell.fm and ict.fm ).