mx.amk-gmbh.com has no NS records.
NS records for this zone are defined at amk-gmbh.com.
NS records for this zone are defined at amk-gmbh.com.
Question and response
Question
dig mx.amk-gmbh.com. NS
Answer
The response has no answer records.
Authority
amk-gmbh.com. 3600 SOA dns.amk-gmbh.com. hostmaster.amk-gmbh.com. 1182708385 43200 3600 604800 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0