Apex domains cannot have CNAME records.
Question and response
Question
dig IX.RU. NS
Answer
ix.ru. 5 NS int2.ix.ru.
ix.ru. 5 NS int3.ix.ru.
ix.ru. 5 NS ns.msk-ix.ru.
Authority
The response has no authority records.
Additional
ns.msk-ix.ru. 5 A 194.226.65.9
int2.ix.ru. 5 A 194.190.145.81
int3.ix.ru. 5 A 194.226.76.90
int3.ix.ru. 5 AAAA 2001:6d0:ffd9:316:194:226:29:50
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0