mail201.convio.net has no CNAME records.
Question and response
Question
dig mail201.convio.net. NS
Answer
The response has no answer records.
Authority
convio.net. 3600 SOA dns1.convio.net. netadmin.convio.com. 2026022602 1800 300 1209600 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0