Well I will just try to finish the post my apologies for this mess. Anyway I found, after some time debugging, that on arch linux you cant share your internet connection with the tetra using the setup script wp6.sh when docker is running. On my computer docker made use of 172.*.*.* as an internal ip. I fixed it with shutting down docker and the docker socket, after this it worked flawlessly.
I did not try to use another ip for the local docker network or make docker work together with the tetra.
I hope this helps somebody!