dns2.univ.com.br has no NS records.
NS records for this zone are defined at univ.com.br.
NS records for this zone are defined at univ.com.br.
Question and response
Question
dig dns2.univ.com.br. NS
Answer
The response has no answer records.
Authority
univ.com.br. 3600 SOA dns1.univ.com.br. hostmaster.univ.com.br. 2022103103 3600 1800 1209600 3600
Additional
. 0 OPT ; payload 1680, xrcode 0, version 0, flags 0