mx.insurethathorse.com has no NS records.
NS records for this zone are defined at insurethathorse.com.
NS records for this zone are defined at insurethathorse.com.
Question and response
Question
dig mx.insurethathorse.com. NS
Answer
The response has no answer records.
Authority
insurethathorse.com. 3600 SOA dns.insurethathorse.com. hostmaster.insurethathorse.com. 1508008819 43200 3600 604800 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0