relay.blacknight.com has no CNAME records.
Question and response
Question
dig relay.blacknight.com. NS
Answer
The response has no answer records.
Authority
blacknight.com. 2753 SOA ns1.blacknight.com. hostmaster.blacknight.com. 1276183043 14400 7200 2419200 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0