smtp.tng.de has no NS records.
NS records for this zone are defined at tng.de.
NS records for this zone are defined at tng.de.
Question and response
Question
dig smtp.mailcluster.tng.de. NS
Answer
The response has no answer records.
Authority
tng.de. 1800 SOA ns1.ennit.net. hostmaster.tng.de. 2026030302 14400 1800 3600000 86400
Additional
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0