IPv6 Tunnel Routing Loops

This RFC seems to explain the problem described below--it is not an error at Freenet6, but a deeper problem with IPv6 tunnels!


Freenet6 Routing Problem

A student's question led me to discover this.

If I traceroute over IPv6 to an address that exists inside Freenet6, it works fine, as shown below.

But if I use an address that doesn't exist, I hit a routing loop.

If I use various Web-based traceroute sites, starting different locations, I get many different results--some fail to give any responses, others still end up looping, but between different servers.

What's going on at Freenet6? It seems to be something like this:

It's a very strange way to route a network. I wonder why?

I saw that someone else had also noticed this in the Freenet6 forums, but no one had any explanation for it.

Originally posted 10-6-10 11:00 am PST

RFC link added 8-24-11