mx02.h.shortest-route.com has no NS records.
NS records for this zone are defined at shortest-route.com.
NS records for this zone are defined at shortest-route.com.
Question and response
Question
dig mx02.h.shortest-route.com. NS
Answer
The response has no answer records.
Authority
shortest-route.com. 86400 SOA ns1.shortest-route.com. hostmaster.shortest-route.com. 2025121500 7200 1800 604800 86400
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0