go
j.ns.se has one IP number , which also has a corresponding reverse pointer. se use this as a nameserver. j.ns.se is hosted on a server in Canada even though the hostname implies Sweden.

j.ns.se
a records
 
+ 199.254.63.1 199.254.63.0/24 AS12041 -
+ --- -
ip numbers of host
199.254.63.1
ptrs of ip numbers
j.ns.se
ip numbers using ptr to this host
199.254.63.1
domains using this as nameserver
se