fwdproxy-ncg-000.fbsv.net has no CNAME records.
Question and response
Question
dig fwdproxy-ncg-000.fbsv.net. NS
Answer
The response has no answer records.
Authority
fbsv.net. 1768 SOA a.ns.facebook.com. dns.facebook.com. 4207849484 14400 1800 604800 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0