said by RR Conductor:
I just ran a test using Comcast's 6to4 Relay, and got this-
Speed tests are going to be highly inconsistent on 6to4. Comcast's relay is only for outbound traffic on 6to4 and has nothing to do with your inbound 6to4 path. That's determined by the network you're trying to connect to. They use their nearest 6to4 relay to send to you.