nsb.ras.ru has no NS records.
NS records for this zone are defined at ras.ru.
NS records for this zone are defined at ras.ru.
Question and response
Question
dig nsb.ras.ru. NS
Answer
The response has no answer records.
Authority
ras.ru. 600 SOA nsa.ras.ru. postmaster.pran.ru. 2025122200 7200 1800 604800 600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0