docker.for.msk.ru has no NS records.
NS records for this zone are defined at for.msk.ru.
NS records for this zone are defined at for.msk.ru.
Question and response
Question
dig docker.for.msk.ru. NS
Answer
The response has no answer records.
Authority
for.msk.ru. 1800 SOA troy.ns.cloudflare.com. dns.cloudflare.com. 2398784069 10000 2400 604800 1800
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0