We pick j.root-servers.net, one of the 13 root servers (1), and ask it about j.pl and learn that pl is delegated to eight name servers (2), so we ask i-dns.pl where we learn that j.pl is delegated to two name servers, including ns1.cba.pl (3), so we ask that one and get the following answer:
J.pl is a domain controlled by two domain name servers at cba.pl. Both are on the same IP network. Incoming mail for j.pl is handled by one mail server at j.pl themselves. J.pl has two IP numbers (95.211.144.87, 95.211.144.89). Both are on the same IP network.
Most of the more than two hundred domains that use the name server ns2.cba.pl use the two name servers ns1 and ns2.cba.pl together, hereafter referred to as "name server group 1", (example: jkw-sc.com, inhome.biz and frbs.org ).
The IP number 95.211.144.87 only
There are several thousand of host names that point only to the IP number 95.211.144.87.