mail.IMT.SU has no NS records.
NS records for this zone are defined at IMT.SU.
NS records for this zone are defined at IMT.SU.
Question and response
Question
dig mail.IMT.SU. NS
Answer
The response has no answer records.
Authority
IMT.SU. 86400 SOA ns1.imt.ru. imt.ru. 2026030578 28800 7200 1209600 86400
Additional
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0