dns-second02.ilk.de has no CNAME records.
Question and response
Question
dig dns-second02.ilk.de. NS
Answer
The response has no answer records.
Authority
ilk.de. 3459 SOA soa1.ilk.net. hostmaster.ilk.net. 2026012200 28800 7200 3600000 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0