mx.cloudz.jp has no NS records.
NS records for this zone are defined at cloudz.jp.
NS records for this zone are defined at cloudz.jp.
Question and response
Question
dig mx.cloudz.jp. NS
Answer
The response has no answer records.
Authority
cloudz.jp. 900 SOA ns000.d-53.net. dns-managers.iij.ad.jp. 1036 3600 600 604800 900
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0