ns2.ocn.ad.jp has no NS records.
NS records for this zone are defined at ocn.ad.jp.
NS records for this zone are defined at ocn.ad.jp.
Question and response
Question
dig ns2.ocn.ad.jp. NS
Answer
The response has no answer records.
Authority
ocn.ad.jp. 600 SOA ns1.ocn.ad.jp. postmaster.ocn.ad.jp. 20403 10800 3600 604800 600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0