mx.fsa2001.com has no NS records.
NS records for this zone are defined at fsa2001.com.
NS records for this zone are defined at fsa2001.com.
Question and response
Question
dig mx.fsa2001.com. NS
Answer
The response has no answer records.
Authority
fsa2001.com. 3600 SOA dns.fsa2001.com. hostmaster.fsa2001.com. 1511716104 43200 3600 604800 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0