mail.prepaires.de has no NS records.
NS records for this zone are defined at prepaires.de.
NS records for this zone are defined at prepaires.de.
Question and response
Question
dig mail.prepaires.de. NS
Answer
The response has no answer records.
Authority
prepaires.de. 3601 SOA dns1.registrar-servers.com. hostmaster.registrar-servers.com. 1773151027 43200 3600 604800 3601
Additional
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0