mx40.sunrise.net has no NS records.
NS records for this zone are defined at sunrise.net.
NS records for this zone are defined at sunrise.net.
Question and response
Question
dig mx40.sunrise.net. NS
Answer
The response has no answer records.
Authority
sunrise.net. 3600 SOA dns1.sunrise.ch. business-support.sunrise.net. 2026021708 28800 3600 604800 3600
Additional
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0