mx.straubsteins.com has no NS records.
NS records for this zone are defined at straubsteins.com.
NS records for this zone are defined at straubsteins.com.
Question and response
Question
dig mx.straubsteins.com. NS
Answer
The response has no answer records.
Authority
straubsteins.com. 3600 SOA dns.straubsteins.com. hostmaster.straubsteins.com. 1665905733 43200 3600 604800 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0