mx02.arz.at has no NS records.
NS records for this zone are defined at arz.at.
NS records for this zone are defined at arz.at.
Question and response
Question
dig mx02.arz.at. NS
Answer
The response has no answer records.
Authority
arz.at. 60 SOA nsi.local. dns-admin.arz.at. 1197 10800 3600 1209600 60
Additional
. 0 OPT ; payload 1220, xrcode 0, version 0, flags 0