We pick d.root-servers.net, one of the 13 root servers (1), and ask it about cityjeans.pl and learn that pl is delegated to eight name servers (2), so we ask h-dns.pl where we learn that cityjeans.pl is delegated to two name servers, including ns2.webexperience.pl (3), so we ask that one and get the following answer:
Cityjeans.pl is a domain controlled by two domain name servers at webexperience.pl. Both are on the same IP network. Incoming mail for cityjeans.pl is handled by seven mail servers at cityjeans.pl themselves having a total of 48 IP numbers. There are 26 duplicated IP numbers. Some of them are on the same IP network. Cityjeans.pl has one IP number (77.79.194.202), but the reverse is atm.webexperience.pl.