mail.pucmmsti.edu.do has no NS records.
NS records for this zone are defined at pucmmsti.edu.do.
NS records for this zone are defined at pucmmsti.edu.do.
Question and response
Question
dig mail.pucmmsti.edu.do. NS
Answer
The response has no answer records.
Authority
pucmmsti.edu.do. 86400 SOA ns1.pucmm.edu.do. postmaster.pucmm.edu.do. 2014061813 3600 60 604800 86400
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0