mx.ohamgroup.com has no NS records.
NS records for this zone are defined at ohamgroup.com.
NS records for this zone are defined at ohamgroup.com.
Question and response
Question
dig mx.ohamgroup.com. NS
Answer
The response has no answer records.
Authority
ohamgroup.com. 3600 SOA dns.ohamgroup.com. hostmaster.ohamgroup.com. 1273614680 43200 3600 604800 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0