got myself a nice little edgerouter X from ubiquity.
I was reading the wiki on how to setup the system and something does not ring properly in my head. ( must be the pills I take 😉 )
So here : http://wiki.ampr.org/wiki/Setting_up_a_gateway_on_Ubiquiti_EdgeRouter
Note that that article does not describe a complete configuration for an AMPRnet IPIP gateway. Maybe it was just a first attempt at writing a WiKi article, maybe the author did not realize that this method is not correct. With this configuration you would only be able to connect towards internet (which he proves by testing) but not to fellow AMPRnet participants. That requires quite some more effort, see what Marius has created for the MikroTik routers.
Rob