Hello k-plan.
OK, I’ll do my best to translate this complex issue. It was hard enough to understand the terms of networking in German. I hope that my Native speakers are available to support my efforts.
So be merciful to me. I try hard. 
I will open a new thread and link with this thread and vice versa.
Otherwise, don’t worry. I’m not going to fumble around on my router. Previously should drop my fingers. 
Regards Thomas