We pick f.root-servers.net, one of the 13 root servers (1), and ask it about gmec.it and learn that it is delegated to six name servers (2), so we ask m.dns.it where we learn that gmec.it is delegated to two name servers, including adlhost59.adlweb.com (3), so we ask that one and get the following answer:
Gmec.it is a domain controlled by two domain name servers at adlweb.com. Both are on the same IP network. Incoming mail for gmec.it is handled by one mail server also at adlweb.com.
All of the about fourty domains that use the primary name server adlhost55.adlweb.com use name server group 1 (example: ariawin.it, ememo.it and adlgroup.it ). Worth noting is that two thirds of the domains that use name server group 1 use the primary name server adlhost55.adlweb.com.
The two name servers adlhost55 and adlhost59.adlweb.com together
There are about sixty domains that use name server group 1.