Windows Peer to Peer Global_ Group without third party ipv6 tunnel

Question

I have been trying to develop a peer to peer application that uses Micosoft's Peer to Peer Group library. Basing my work on the Creating a Group Chat Application acrticle on msdn. This works fine for local groups and will also work for global groups if I have a thrid party tunnel adapter installed such as the gogo6 client. However from a few things I have read it seems like I should be able to get things working through the Teredo tunnel adapter that comes built into Windows.

I have tried various things and can now access ipv6 only sites (eg ipv6.google.com) without the gogo6 tunnel running, but I can't seem to find any other peers in my global group through this method.

I have added a rule allowing trafic (including edge traversal) for the application in the Windows Firewall and also opened the following ports to incoming and outgoing trafic.

• tcp 3587
• udp 3540, 1900

From the samples I have read it seems like it should just work, but it doesn't. I did read that to use teredo in an application you had to specificaly enable it. The only way I have found to do this is when opening the socket, but the group api does all of that for you so I have no known way of controlling that.

Answer 1

I don't think Teredo supports IPv6 multicast. If the Peer to Peer Group library uses multicast under the hood, I think that's the problem. I could never find any confirmation that multicast is unsupported by Teredo; but in my own testing setsockopt(ADD_GROUP_MEMBERSHIP) would always fail when the interface ID was a Teredo interface.

Answer 2

Some Teredo clients are unreachable due to symmetric router problem. Teredo can work only behind 90% of routers. Gogo6 uses TSP which tunnels the packet to gogo6 infrastructure from where it reaches ipv6 internet.