mail.ipwtech.com has no NS records.
NS records for this zone are defined at ipwtech.com.
NS records for this zone are defined at ipwtech.com.
Question and response
Question
dig mail.ipwtech.com. NS
Answer
The response has no answer records.
Authority
ipwtech.com. 300 SOA klv2.ipwtech.com. root.klv2.ipwtech.com. 1252548409 3600 3600 604800 300
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0