mx2.123.net has no NS records.
NS records for this zone are defined at 123.net.
NS records for this zone are defined at 123.net.
Question and response
Question
dig mx2.123.net. NS
Answer
The response has no answer records.
Authority
123.net. 3600 SOA ns2.distance.net. dns.distance.net. 2026022701 3600 600 1209600 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0