As I mentioned in a previous post, I installed dd-wrt (kernel 2.6, VOIP, build 14896) on my wireless router (Linksys WRT320N), which connected to a VDSL modem using PPPoE. After that, it worked fine for IPv4, so I had the same functionality as the original Linksys firmware. However, the purpose of the exercise was to get IPv6 support: this turned out to be easier said than done. I was eventually able to get it working, so if you only want the short answer and aren’t interested in all the troubleshooting steps that I went through, scroll down to the Conclusion section at the bottom of this post.
Please refer to my IPv6 router post to get an overview of what I’m trying to achieve here. Most of the documentation that I’ve found assumes that you’re using a tunnel: this is similar to a proxy server, where you have an IPv4 connection to a machine on the internet, then that machine connects to your real destination using IPv6. However, I have native IPv6 connectivity from my ISP.