mx.iptox.net has no NS records.
NS records for this zone are defined at iptox.net.
NS records for this zone are defined at iptox.net.
Question and response
Question
dig mx.iptox.net. NS
Answer
The response has no answer records.
Authority
iptox.net. 300 SOA ns1.iptox.net. hostmaster.iptox.net. 2023071801 3600 3600 604800 300
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0