ns02a-bsa.brasiltelecom.net.br has no NS records.
NS records for this zone are defined at brasiltelecom.net.br.
NS records for this zone are defined at brasiltelecom.net.br.
Question and response
Question
dig ns02a-bsa.brasiltelecom.net.br. NS
Answer
The response has no answer records.
Authority
brasiltelecom.net.br. 600 SOA ns01-cta.brasiltelecom.net.br. dns.brasiltelecom.net.br. 73368 10800 3600 604800 600
Additional
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0