smtp-relay.tamu.edu has no NS records.
NS records for this zone are defined at tamu.edu.
NS records for this zone are defined at tamu.edu.
Question and response
Question
dig smtp-relay.tamu.edu. NS
Answer
The response has no answer records.
Authority
tamu.edu. 900 SOA csce-info-grid.net.tamu.edu. infoblox.tamu.edu. 11477873 14400 1440 2419200 900
Additional
. 0 OPT ; payload 1220, xrcode 0, version 0, flags 0