ns4.digital.rt.ru has no CNAME records.
Question and response
Question
dig ns4.digital.rt.ru. NS
Answer
The response has no answer records.
Authority
digital.rt.ru. 8123 SOA ns1.digital.rt.ru. hostmaster.digital.rt.ru. 2026020400 28800 7200 604800 86400
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0