mail.penza.com.ru has no NS records.
NS records for this zone are defined at penza.com.ru.
NS records for this zone are defined at penza.com.ru.
Question and response
Question
dig mail.penza.com.ru. NS
Answer
The response has no answer records.
Authority
penza.com.ru. 1200 SOA ns.penza.com.ru. dnsmaster.penza.com.ru. 2025111801 14400 3600 1814400 1200
Additional
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0