travelclick.com.s7b2.psmtp.com has no NS records.
NS records for this zone are defined at psmtp.com.
NS records for this zone are defined at psmtp.com.
Question and response
Question
dig travelclick.com.s7b2.psmtp.com. NS
Answer
The response has no answer records.
Authority
psmtp.com. 60 SOA ns1.google.com. dns-admin.google.com. 884330780 900 900 1800 60
Additional
. 0 OPT ; payload 512, xrcode 0, version 0, flags 0