dns1.virtua.com.br has no CNAME records.
Question and response
Question
dig dns1.virtua.com.br. NS
Answer
The response has no answer records.
Authority
virtua.com.br. 300 SOA root.virtua.com.br. postmaster.virtua.com.br. 2026030402 300 300 86400 300
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0