dns2.grz.at has no NS records.
NS records for this zone are defined at grz.at.
NS records for this zone are defined at grz.at.
Question and response
Question
dig dns2.grz.at. NS
Answer
The response has no answer records.
Authority
grz.at. 1800 SOA dns1.grz.at. hostmaster.grz.at. 2017081246 1800 600 1209600 1800
Additional
. 0 OPT ; payload 1400, xrcode 0, version 0, flags 0