4in6 tunneling (via OpenVPN?)

Solution 1:

The answer is simple.

1. Set up a VPS with IPv6 connectivity and set up OpenVPN using a TAP interface (as opposed to TUN) on both the VPS and your local machine. Make sure you are connecting to the VPS over IPv6.
2. Make sure the TAP interfaces on both ends have private IPv4 addresses on the same subnet. Ping the VPS's private IPv4 address to make sure you have a connection.
3. Enable IPv4 forwarding and NAT masquerading on the VPS: echo 1 > /proc/sys/net/ipv4/ip_forward, iptables -t nat -A POSTROUTING -o eth0 -j MASQUERADE
4. On your local machine, delete the default IPv4 route: ip -4 route del default
5. Add a new default IPv4 route on your local machine, using the VPS's private IPv4 address as the gateway: ip -4 route add default via 10.20.30.1 (assuming 10.20.30.1 is the IP address on the VPS's TAP interface)

I used this process (but in reverse) to get a IPv6 connection before my ISP provided one. EDIS GmbH offers cheap VPS with an IPv6 address in various countries. They have a multitude of options and Linux flavors to install as well.

Solution 2:

A virtual server approach will require lots of fiddling, actually setting up a cloud computer hosted on a provider that supports IPv6. While such providers exist, I'm not convinced that VPS is the only solution.

It seems to me that you require a cloud Tunnel broker provider that provides "IPv4 over IPv6", using your router's IPv6 capabilities to connect to that service. That is, using an IPv6 router you would like to access IPv4 networks.

Unfortunately, most tunnel brokers give the opposite service of "IPv6 over IPv4", for people having IPv4 routers but needing to access IPv6 networks.

Some useful info is contained in the Wikipedia article List of IPv6 tunnel brokers, where you should be looking for providers that support 4in6 and Tunnel Setup Protocol (TSP).

One likely candidate is Freenet6 and their free service Freenet6 DS-lite (Beta). I have no experience with it and the documentation is sparse, but you could try and see if it is useful. I do not know the bandwidth of this free service or if a faster commercial service is available. You would have to contact their Support for that.

SIXXS seems like another good candidate.