c-73-128-76-142.hsd1.dc.comcast.net has no CNAME records.
Question and response
Question
dig c-73-128-76-142.hsd1.dc.comcast.net. NS
Answer
The response has no answer records.
Authority
hsd1.dc.comcast.net. 791 SOA dns101.comcast.net. dnsadmin.comcast.net. 1755769 7200 3600 604800 900
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0