mailfilter.hostnet.nl has no NS records.
NS records for this zone are defined at hostnet.nl.
NS records for this zone are defined at hostnet.nl.
Question and response
Question
dig mailfilter.hostnet.nl. NS
Answer
The response has no answer records.
Authority
hostnet.nl. 300 SOA ns01.authdns.hostnet.nl. hostmaster.hostnet.nl. 2026022001 1800 900 1209600 300
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0