ns2.den.ru has no NS records.
NS records for this zone are defined at den.ru.
NS records for this zone are defined at den.ru.
Question and response
Question
dig ns2.den.ru. NS
Answer
The response has no answer records.
Authority
den.ru. 86400 SOA ve.nu. hostmaster.den.ru. 2025080201 10800 3600 3600000 86400
Additional
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0