mail.net.tamu.edu has no NS records.
NS records for this zone are defined at net.tamu.edu.
NS records for this zone are defined at net.tamu.edu.
Question and response
Question
dig mail.net.tamu.edu. NS
Answer
The response has no answer records.
Authority
net.tamu.edu. 900 SOA ns1.tamu.edu. infoblox.tamu.edu. 66273 14400 3600 2419200 900
Additional
. 0 OPT ; payload 1220, xrcode 0, version 0, flags 0