post.mpcdf.mpg.de has no CNAME records.
Question and response
Question
dig post.mpcdf.mpg.de. NS
Answer
The response has no answer records.
Authority
mpcdf.mpg.de. 10800 SOA sat.mpcdf.mpg.de. hostmaster.mpcdf.mpg.de. 2026022500 86400 1800 2419200 10800
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0