cdn.ngenix.net has no NS records.
NS records for this zone are defined at ngenix.net.
NS records for this zone are defined at ngenix.net.
Question and response
Question
dig cdn.ngenix.net. NS
Answer
The response has no answer records.
Authority
ngenix.net. 300 SOA ns.ngenix.net. noc.ngenix.net. 1 7200 600 1209600 300
Additional
. 0 OPT ; payload 1024, xrcode 0, version 0, flags 0