mail.SIBMEDIAFON.RU has no NS records.
NS records for this zone are defined at SIBMEDIAFON.RU.
NS records for this zone are defined at SIBMEDIAFON.RU.
Question and response
Question
dig mail.SIBMEDIAFON.RU. NS
Answer
The response has no answer records.
Authority
sibmediafon.ru. 3600 SOA ns.sibmediafon.ru. root.sibmediafon.ru. 2018042001 7200 900 3600000 36000
Additional
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0