f.dns.RIPN.net has no CNAME records.
Question and response
Question
dig f.dns.RIPN.net. NS
Answer
The response has no answer records.
Authority
RIPN.net. 1800 SOA a.dns.RIPN.net. noc-dns.msk-ix.ru. 27013605 14400 3600 2592000 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0