mx.secureweb.jp has no NS records.
NS records for this zone are defined at secureweb.jp.
NS records for this zone are defined at secureweb.jp.
Question and response
Question
dig mx.secureweb.jp. NS
Answer
The response has no answer records.
Authority
secureweb.jp. 900 SOA ns-e.secureweb.jp. dns-managers.iij.ad.jp. 124 3600 1800 3600000 900
Additional
. 0 OPT ; payload 1220, xrcode 0, version 0, flags 0