smtp.mppmu.mpg.de has no NS records.
NS records for this zone are defined at mppmu.mpg.de.
NS records for this zone are defined at mppmu.mpg.de.
Question and response
Question
dig smtp.mppmu.mpg.de. NS
Answer
The response has no answer records.
Authority
mppmu.mpg.de. 600 SOA iws132a.mppmu.mpg.de. uwl.mppmu.mpg.de. 2026030900 10800 1800 604800 3600
Additional
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0