sns02.hkn.de has no CNAME records.
Question and response
Question
dig sns02.hkn.de. NS
Answer
The response has no answer records.
Authority
hkn.de. 300 SOA neos.hkn.de. hostmaster.hkn.de. 1772337737 28800 7200 604800 300
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0