_netblocks.viawest.net has no CNAME records.
Question and response
Question
dig _netblocks.viawest.net. NS
Answer
The response has no answer records.
Authority
viawest.net. 270 SOA ns1.viawest.net. hostmaster.viawest.net. 2025111000 3600 1800 1209600 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0