tuminfo2.in.tum.de has no CNAME records.
Question and response
Question
dig tuminfo2.in.tum.de. NS
Answer
The response has no answer records.
Authority
in.tum.de. 907 SOA ns1.rbg.tum.de. postmaster.rbg.tum.de. 1500257868 21600 1800 360000 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0