mail.redni.edu.do has no NS records.
NS records for this zone are defined at redni.edu.do.
NS records for this zone are defined at redni.edu.do.
Question and response
Question
dig mail.redni.edu.do. NS
Answer
The response has no answer records.
Authority
redni.edu.do. 1800 SOA ns1.digitalocean.com. hostmaster.redni.edu.do. 1764945078 10800 3600 604800 1800
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0