mx2.unipol.ru has no NS records.
NS records for this zone are defined at unipol.ru.
NS records for this zone are defined at unipol.ru.
Question and response
Question
dig mx2.unipol.ru. NS
Answer
The response has no answer records.
Authority
unipol.ru. 900 SOA dns1.yandex.net. dns-hosting.yandex.ru. 24 900 90 86400 900
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0