Nov 07 11:40 2013, Michiel van der Vlist wrote to Markus Reschke:
MvdV> relays. Plus that - correct me if I am wrong - it is my MvdV> understanding that Teredo does not work from behind double NAT.
AFAIK it doesn't support symmetric NAT. So double NAT might work based on the NAT methods used by the firewalls/routers.
MvdV> But wait.... We do not need third parties to provide gateways. In MvdV> Fidonet we already have a mechanism to get messages from one system MvdV> to another if they can't connect directly. It is called routed MvdV> mail. Any dual capability node can act as a gateway between IPv4 MvdV> only and IPv6 only nodes.