postrelay1b.lrz.de has no CNAME records.
Question and response
Question
dig postrelay1b.lrz.de. NS
Answer
The response has no answer records.
Authority
lrz.de. 36595 SOA dns1.lrz.de. hostmaster.lrz.de. 2026021057 21600 1800 3600000 86400
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0