mx.discountdevelop.com has no NS records.
NS records for this zone are defined at discountdevelop.com.
NS records for this zone are defined at discountdevelop.com.
Question and response
Question
dig mx.discountdevelop.com. NS
Answer
The response has no answer records.
Authority
discountdevelop.com. 3600 SOA dns.discountdevelop.com. hostmaster.discountdevelop.com. 1260274494 43200 3600 604800 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0