dns-upper-redirect.xfinity.com has no CNAME records.
Question and response
Question
dig dns-upper-redirect.xfinity.com. NS
Answer
The response has no answer records.
Authority
xfinity.com. 791 SOA dns101.comcast.net. dnsadmin.comcast.net. 2015042173 7200 3600 604800 900
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0