nsauth1.osd.surfsara.nl has no NS records.
NS records for this zone are defined at osd.surfsara.nl.
NS records for this zone are defined at osd.surfsara.nl.
Question and response
Question
dig nsauth1.osd.surfsara.nl. NS
Answer
The response has no answer records.
Authority
osd.surfsara.nl. 3600 SOA nsauth1.surfsara.nl. dns-admin.surfsara.nl. 2603251116 7200 600 604800 86400
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0