mailgw2.knv.de has no CNAME records.
Question and response
Question
dig mailgw2.knv.de. NS
Answer
The response has no answer records.
Authority
knv.de. 10800 SOA dns1.cscdns.net. hostmaster.cscdns.net. 2026010903 14400 7200 1209600 28800
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0