biscmail.cv.net has no NS records.
NS records for this zone are defined at cv.net.
NS records for this zone are defined at cv.net.
Question and response
Question
dig biscmail.cv.net. NS
Answer
The response has no answer records.
Authority
cv.net. 3600 SOA authns1.cv.net. abuse.optimum.net. 2013419770 7200 600 604800 3600
Additional
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0