pm.gtnet.ru has no CNAME records.
Question and response
Question
dig pm.gtnet.ru. NS
Answer
The response has no answer records.
Authority
gtnet.ru. 552 SOA inn361.ru. inn.inn361.ru.gtnet.ru. 2026020902 86400 3600 604800 345600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0