mx2.ntelecom.com.br has no NS records.
NS records for this zone are defined at ntelecom.com.br.
NS records for this zone are defined at ntelecom.com.br.
Question and response
Question
dig mx2.ntelecom.com.br. NS
Answer
The response has no answer records.
Authority
ntelecom.com.br. 600 SOA srv1.ntelecom.com.br. postmaster.ntelecom.com.br. 2024041600 3600 900 1209600 43200
Additional
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0