I slapped together a video presentation on setting up a Linux tunnel behind a firewall that passes Protocol41:http://www.youtube.com/watch?v=4o7sk97mItM
Full resolution version here: http://broquea.corp.he.net/videos/tutorial.ogv
(Ogg/Vorbis/Theor0a, used recordMyDesktop under Linux)
^^^ is what i was talking about broquea, that video
I have a Cisco AE4500 which is just a decent N900 consumer router. I don't know if this router "passes protocol 41."
- and - according to a screenshot of the E4200 Cisco/Linksys this router really sucks. I do not like the interface on it at all. Work gave it to me for free.
(E4200 has a much nicer interface)
thought this screen shot might help but i still am not getting it to work: http://www.tunnelbroker.net/forums/index.php?topic=1850.0