pop.ispsupport.net has no NS records.
NS records for this zone are defined at ispsupport.net.
NS records for this zone are defined at ispsupport.net.
Question and response
Question
dig pop.ispsupport.net. NS
Answer
The response has no answer records.
Authority
ispsupport.net. 86400 SOA ns1.ispsupport.com. hostmaster.ispsupport.com. 2009031904 10800 3600 604800 86400
Additional
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0