I think maybe it is more like a windows problem, than an IPV6 problem.
I configured an PPTP server with IPV6. In the first several minutes just after successfully connection, my laptop can access ipv6 with no problem. The default gateway for ::/0 was right at that time. However after a few minutes, the default gateway ::/0 mysteriously disappeared. If I manually add route for ::/0, everything went fine ever after.
Just want to ask guys who have an idea why the windows seems stupid lost the right gateway.
(I am using Windows 7)
PPP (and by extension PPTP) only configures link-local IPs when IPv6 is enabled for it. You need to have something like RA or DHCPv6 running to handle requests on the link to assign any additional parameters, such as the available gateways, prefixes, etc. Basically, unless you fire up either of those, you'll need to setup manual settings for route, local address, etc. If you do have either setup, ensure you're not getting another RA/DHCPv6 reply during that time trashing your existing values.