Summary
ns0.nic.ad.jp has one IP number , which also has a corresponding reverse pointer.
b.dns.jp point to the same IP.
nic.ad.jp is a domain controlled by two nameservers at
nic.ad.jp themselves. They are on the same IP network. Incoming mail for
nic.ad.jp is handled by two mailservers also at
nic.ad.jp. They are on the same IP network.
nic.ad.jp has one IP number.
ns0.nic.ad.jp is hosted on a server in Asia/Pacific Region even though the hostname implies Japan.