ns4.sidn.nl has no NS records.
NS records for this zone are defined at sidn.nl.
NS records for this zone are defined at sidn.nl.
Question and response
Question
dig ns4.sidn.nl. NS
Answer
The response has no answer records.
Authority
sidn.nl. 300 SOA ns4.sidn.nl. hostmaster.sidn.nl. 1773155432 14400 3600 3456000 300
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0