ns1.kpn.net has no NS records.
NS records for this zone are defined at kpn.net.
NS records for this zone are defined at kpn.net.
Question and response
Question
dig ns1.kpn.net. NS
Answer
The response has no answer records.
Authority
kpn.net. 300 SOA ns1.kpn.net. zonemaster.kpn.com. 2026031202 28800 3600 1209600 300
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0