as1.bluemarble.net has no CNAME records.
Question and response
Question
dig as1.bluemarble.net. NS
Answer
The response has no answer records.
Authority
bluemarble.net. 1470 SOA as1.bluemarble.net. hostmaster.bluemarble.net. 2025121602 7200 3600 1209600 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0