mx01.udag.de has no NS records.
NS records for this zone are defined at udag.de.
NS records for this zone are defined at udag.de.
Question and response
Question
dig mx01.udag.de. NS
Answer
The response has no answer records.
Authority
udag.de. 3600 SOA ns.udag.de. hostmaster.united-domains.de. 2024093019 10800 3600 604800 3600
Additional
. 0 OPT ; payload 1220, xrcode 0, version 0, flags 0