We are looking to compile a list of firewall/CPE devices that by default (With no major changes except maybe a firmware update) support IPv6 over IPv4 tunnels. (Protocol 41 tunneling).
If you are passing your tunnel over a commercial firewall to terminate on a machine behind it, then please let us know what version hardware and firmware you are having success with.
So far we have tested in house:
# Linksys WRT54G firmware 4.21.2
All of which work.
I am trying to set up a tunnel as well. I have a Linksys WRT54G router, everything seems fine according to HE technical support so either the router doens't support protocol 41 or my ISP. But my router's firmware is v1.02.8. And this is Linksys WRT54G ver 6. The version could mean anything? For this router this is the latest version of firmware.
I too have the WRT54G router and all my tries gettin that thing to work failed (even DMZ and turning off all firewalls). In the end I had to connect the laptop directly to the modem.
But since you have a flashable version of the router, you could look out for the alternative firmwares ddwrt and open wrt. Both of them allow IPv6 tunneling.