We pick c.root-servers.net, one of the 13 root servers (1), and ask it about tld.pl and learn that pl is delegated to eight name servers (2), so we ask d-dns.pl where we learn that tld.pl is delegated to two name servers, including ns1.tld.pl (3), so we ask that one and get the following answer:
Tld.pl is a domain controlled by two domain name servers at tld.pl themselves. Both are on different IP networks. Incoming mail for tld.pl is handled by one mail server also at tld.pl. Tld.pl has one IP number (195.149.224.126), which also has a corresponding reverse pointer.
All of the six host names that point to the IP number 195.149.224.126 point only to that ip number.
The name server ns2.tld.pl
Most of the more than hundred domains that use the name server ns2.tld.pl use the two name servers ns1 and ns2.tld.pl together, hereafter referred to as "name server group 1", (example: zarzadcy.biz, c-swde.com and e-sgh.com ).
