isp.ortel.ru has no CNAME records.
Question and response
Question
dig isp.ortel.ru. NS
Answer
The response has no answer records.
Authority
ortel.ru. 3600 SOA ns.ortel.ru. hostmaster.ortel.ru. 2026021101 7200 7200 604800 86400
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0