Let me explain my szenario:

I have a linux server A. A is reachable in a VPN. So if I am connected to the VPN over Internet I can successfully ping A.

Server A is connected to a Router B. Router B has a local ipv6 address and there are resources (each of them with a local ipv6 address) connected to Router B.

After I am connected to VPN, I am able to use ssh to have access over A. Now I can use the ping6 command to ping the Router B or one of its connected resources.

This works fine. The ping fails if I try to ping router B on my computer.

Overview:

My Computer --> VPN --> Server A(ipv4) --> Router B(ipv6) --> Ressource A(ipv6)

On resource A runs for example a HTTP-Server.

My question is: How can I access Resource A (for example with HTTP) on my to VPN connected computer? Is it possible? Should I setup a tunnel device?

Sorry for this inexpertly explanation, but I am new to network stuff!