mail.silinet.ru has no CNAME records.
Question and response
Question
dig mail.silinet.ru. NS
Answer
The response has no answer records.
Authority
silinet.ru. 600 SOA ns1.fiord.ru. noc.fiord.ru. 2024110832 14400 1800 2592000 86400
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0