ns.GAZPROM.RU has no CNAME records.
Question and response
Question
dig ns.GAZPROM.RU. NS
Answer
The response has no answer records.
Authority
gazprom.ru. 2526 SOA ns.gazprom.ru. sysadm.gazprom.ru. 2026030502 900 900 604800 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0