auth3.dns.rcn.net has no CNAME records.
Question and response
Question
dig auth3.dns.rcn.net. NS
Answer
The response has no answer records.
Authority
DNS.rcn.net. 2099 SOA master.DNS.rcn.net. hostmaster.rcn.com. 2025080801 10800 3600 604800 86400
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0