We pick l.root-servers.net, one of the 13 root servers (1), and ask it about k.info.pl and learn that pl is delegated to eight name servers (2), so we ask h-dns.pl where we learn that k.info.pl is delegated to two name servers, including ns2.ibc.pl (3), so we ask that one and get the following answer:
K.info.pl is a domain controlled by two domain name servers at ibc.pl. Both are on different IP networks. Incoming mail for k.info.pl is handled by one mail server at k.info.pl themselves. K.info.pl has one IP number (94.152.195.105), but the reverse is 5.ibc.pl.
K.info.pl uses the primary name server ns1.ibc.pl, the two name servers ns1 and ns2.ibc.pl together, hereafter referred to as "name server group 1", the IPv4 number 94.152.195.105 only and the primary mail server k.info.pl.
The primary name server ns1.ibc.pl only
All of the several hundred of domains that use the primary name server ns1.ibc.pl use name server group 1 (example: auto-plus.org, breloki.com and anpol-poznan.com.pl ). Worth noting is that a third of the domains that use name server group 1 use the primary name server ns1.ibc.pl.
The IPv4 number 94.152.195.105 only
There are more than hundred domains that only use the IPv4 number 94.152.195.105.