mx.justjoann.net has no NS records.
NS records for this zone are defined at justjoann.net.
NS records for this zone are defined at justjoann.net.
Question and response
Question
dig mx.justjoann.net. NS
Answer
The response has no answer records.
Authority
justjoann.net. 3600 SOA dns.justjoann.net. hostmaster.justjoann.net. 1424182665 43200 3600 604800 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0