We pick k.root-servers.net, one of the 13 root servers (1), and ask it about gts.pl and learn that pl is delegated to eight name servers (2), so we ask e-dns.pl where we learn that gts.pl is delegated to three name servers, including ns4.ikp.pl (3), so we ask that one and get the following answer:
The three mail servers mail.ikp.pl, mx.ikp.pl and mx0.ipartners.pl together
Three quarter of the more than hundred domains that use mail server group 1 use name server group 1 (example: elba.pl, aat.pl and e-kartoteka.pl ). Worth noting is that more than one in eight of the domains that use name server group 1 use mail server group 1.
The three name servers ns1, ns2 and ns4.ikp.pl together
There are almost a thousands domains that use name server group 1.
More than one in eight of those use mail server group 1 (example: pomatonemi.com.pl, datatrans.com.pl and xor.pl ). Worth noting is that two thirds of the domains that use mail server group 1 use name server group 1.
Six percent of them use mail server group 3 (example: friendsheep.com and kato.pl ). Worth noting is that two thirds of the domains that use mail server group 3 use name server group 1.
The two mail servers mx.ikp.pl and mx0.ipartners.pl together
Two thirds of the about seventy domains that use mail server group 3 use name server group 1 (example: gardena.com.pl, ikp.pl and uniarty.it.pl ). Worth noting is that five percent of the domains that use name server group 1 use mail server group 3.