mail.brsite.net has no NS records.
NS records for this zone are defined at brsite.net.
NS records for this zone are defined at brsite.net.
Question and response
Question
dig mail.brsite.net. NS
Answer
The response has no answer records.
Authority
brsite.net. 3600 SOA brsite.net. hostmaster.brs.com.br. 2011020300 10800 3600 604800 86300
Additional
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0