mail.dmopp.de has no NS records.
NS records for this zone are defined at dmopp.de.
NS records for this zone are defined at dmopp.de.
Question and response
Question
dig mail.dmopp.de. NS
Answer
The response has no answer records.
Authority
dmopp.de. 600 SOA ns1110.ui-dns.biz. hostmaster.1und1.com. 2017060279 28800 7200 604800 600
Additional
. 0 OPT ; payload 1220, xrcode 0, version 0, flags 0