mx.werk21system.de has no NS records.
NS records for this zone are defined at werk21system.de.
NS records for this zone are defined at werk21system.de.
Question and response
Question
dig mx.werk21system.de. NS
Answer
The response has no answer records.
Authority
werk21system.de. 3600 SOA ns.werk21system.de. hostmaster.werk21.de. 2026030601 86400 900 2592000 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0