go
c.dns.jp has one IP number , which also has a corresponding reverse pointer. jp and dns.jp use this as a nameserver. dns.jp is a domain controlled by seven nameservers at dns.jp themselves. All of them are on different IP networks. Incoming mail for dns.jp is handled by two mailservers at jprs.co.jp. They are on the same IP network. c.dns.jp is hosted on a server in United States even though the hostname implies Japan.

c.dns.jp
a records
 
+ 204.74.112.245 204.74.112.0/24 AS12008 -
+ --- -

dns.jp
ns-soa records
 
+   AS?  
+ ---  
ns records
a.dns.jp
+ 203.119.1.1 203.119.1.0/24 AS23774 -
+ --- -
b.dns.jp
+ 202.12.30.131 202.12.30.0/24 AS2515 ns0.nic.ad.jp
+ --- ns0.nic.ad.jp
d.dns.jp
+ 210.138.175.244 210.138.0.0/16 AS2497 -
+ --- -
e.dns.jp
+ 192.50.43.53 192.50.43.0/24 AS23634 -
f.dns.jp
+ 150.100.2.3 150.100.0.0/16 AS2907 ns-jp.sinet.ad.jp
+ --- ns-jp.sinet.ad.jp
c.dns.jp
+ 204.74.112.245 204.74.112.0/24 AS12008 -
+ --- -
g.dns.jp
+ 203.119.40.1 203.119.40.0/24 AS24252 -
mx records
mx11.jprs.co.jp
+ 202.11.17.116 202.11.16.0/23 AS18149 -
+ --- -
mx12.jprs.co.jp
+ 202.11.17.119 202.11.16.0/23 AS18149 -
ip numbers of host
204.74.112.245
ptrs of ip numbers
c.dns.jp
ip numbers using ptr to this host
204.74.112.245
domains using this as nameserver
dns.jp
jp