On my way into IPv6 land the next stop was in OpenVPN land and to see if I could establish an OpenVPN tunnel over an IPv6 UDP connection. Note that in this scenario I only want to have IPv4 inside the tunnel as before but the tunnel itself should make use of a UDPv6 instead of a UDPv4 connection. Turns out that OpenVPN does support this in principle but one has to decide whether to start the OpenVPN server in IPv4 or IPv6 mode. Dual-stack operation is not yet included. Not ideal, but for testing purposes I would have switched to IPv6 on the server side. Unfortunately it never came to that because the OpenVPN client in Ubuntu’s network manager does not have an option in the GUI and also not in the NetworkManager configuration files to specify UDPv6 as a transport protocol. Quite a pity as it excludes everyone with a Dual-Stack Lite cable modem from installing an OpenVPN server at home and using it together with Ubuntu’s NetworkManager. Perhaps the OpenVPN client can be launched from a shell but where’s the fun in that?