mx.gurushill.com has no NS records.
NS records for this zone are defined at gurushill.com.
NS records for this zone are defined at gurushill.com.
Question and response
Question
dig mx.gurushill.com. NS
Answer
The response has no answer records.
Authority
gurushill.com. 3600 SOA dns.gurushill.com. hostmaster.gurushill.com. 1971236576 43200 3600 604800 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0