We pick g.root-servers.net, one of the 13 root servers (1), and ask it about www.ps and learn that ps is delegated to six name servers (2), so we ask fork.sth.dnsnode.net where we learn that www.ps is delegated to two name servers, including ns2.pnina.ps (3), so we ask that one and get the following answer:
The two mail servers mail and ns2.pnina.ps together
All of the one domains that use the two mail servers mail and ns2.pnina.ps together, hereafter referred to as "mail server group 1", use the three name servers ns1, ns2 and ote.pnina.ps together, hereafter referred to as "name server group 3".
The two name servers ns1 and ns2.pnina.ps together
One of the five domains that use name server group 1 point only to the IP number 208.64.68.60. Worth noting is that one of the host names that point only to the IP number 208.64.68.60 use name server group 1.
The mail server ns1.pnina.ps
There are one domains that use the mail server ns1.pnina.ps.
All of them point only to the IP number 194.6.225.20.
The mail server ns2.pnina.ps
There are one domains that use the mail server ns2.pnina.ps.
All of those use name server group 3.
All of them use mail server group 1.
The IP number 194.6.225.20
All of the one host names that point to the IP number 194.6.225.20 point only to that ip number.
The IP number 208.64.68.60 only
One of the four host names that point only to the IP number 208.64.68.60 use name server group 1. Worth noting is that one of the domains that use name server group 1 point only to the IP number 208.64.68.60.
The IP number 194.6.225.20 only
All of the one host names that point only to the IP number 194.6.225.20 use only the mail server ns1.pnina.ps.