mail4.fwd.ispnet.net has no NS records.
NS records for this zone are defined at fwd.ispnet.net.
NS records for this zone are defined at fwd.ispnet.net.
Question and response
Question
dig mail4.fwd.ispnet.net. NS
Answer
The response has no answer records.
Authority
fwd.ispnet.net. 86400 SOA localhost.fwd.ispnet.net. hostmaster.ispnet.net. 2025121800 7200 3600 1209600 86400
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0