mx.zoneopportunityknocks.com has no NS records.
NS records for this zone are defined at zoneopportunityknocks.com.
NS records for this zone are defined at zoneopportunityknocks.com.
Question and response
Question
dig mx.zoneopportunityknocks.com. NS
Answer
The response has no answer records.
Authority
zoneopportunityknocks.com. 3600 SOA dns.zoneopportunityknocks.com. hostmaster.zoneopportunityknocks.com. 1320376700 43200 3600 604800 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0