as2.bluemarble.net has no CNAME records.
Question and response
Question
dig as2.bluemarble.net. NS
Answer
The response has no answer records.
Authority
bluemarble.net. 2309 SOA as1.bluemarble.net. hostmaster.bluemarble.net. 2025121602 7200 3600 1209600 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0