Apex domains cannot have CNAME records.
Question and response
Question
dig baikal-ix.ru. NS
Answer
baikal-ix.ru. 5 NS ns.ortel.ru.
baikal-ix.ru. 5 NS ns2.dreamnet.su.
baikal-ix.ru. 5 NS ns1.baikal-telecom.net.
Authority
The response has no authority records.
Additional
ns.ortel.ru. 5 A 195.208.14.6
ns1.baikal-telecom.net. 5 A 194.143.148.15
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0