mx.mountainview-m.com has no NS records.
NS records for this zone are defined at mountainview-m.com.
NS records for this zone are defined at mountainview-m.com.
Question and response
Question
dig mx.mountainview-m.com. NS
Answer
The response has no answer records.
Authority
mountainview-m.com. 3600 SOA dns.mountainview-m.com. hostmaster.mountainview-m.com. 1946411216 43200 3600 604800 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0