mail.ports.net has no NS records.
NS records for this zone are defined at ports.net.
NS records for this zone are defined at ports.net.
Question and response
Question
dig mail.ports.net. NS
Answer
The response has no answer records.
Authority
ports.net. 3600 SOA ns1.p201.dns.oraclecloud.net. registry.ports.net. 2026010500 3600 1800 2419200 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0