136.6.21.216.forestracks.net has no CNAME records.
Question and response
Question
dig 136.6.21.216.forestracks.net. NS
Answer
The response has no answer records.
Authority
forestracks.net. 100 SOA evan.ns.cloudflare.com. dns.cloudflare.com. 2398477441 10000 2400 604800 1800
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0