mx.cti.eco.br has no NS records.
NS records for this zone are defined at cti.eco.br.
NS records for this zone are defined at cti.eco.br.
Question and response
Question
dig mx.cti.eco.br. NS
Answer
The response has no answer records.
Authority
cti.eco.br. 300 SOA dns1.ctitech.net.br. postmaster.ctitech.net.br. 2025102402 28800 3600 604800 300
Additional
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0