Problem with Win7 using tunnel

[kasperd]

It also shows a default gateway of fe80::212:3fff:fe24:fe94%10. I would assume that the default gateway in ipv6 is delivered by radvd

It probably is. Technically a link local address as default gateway could work just fine. However typically the address is taken from the address range you are advertising for the segment. It is plausible that some operating systems consider a link local address to be a valid default gateway and others do not. If that is the source of your problem, then one could look at RFCs to figure out which OS to blame. However I guess you are more interested in knowing how to get it working than what OS to blame.

I guess radvd looks at addresses configured on eth0. You should show us the output of ifconfig eth0

which, to my understanding is essentially equivalent to dhcp in ipv4.

They do serve roughly the same purpose, however they work on quite different principles.

I'm not here to be obnoxious

Are you here to help newcomers getting started? I haven't noticed you contributing any useful information to this thread.

I'm beginning to think this is a Windows problem, as I have a Linux laptop and it picks up an ipv6 address (and the -apparently- correct default gateway) from the radvd on the Linux server and alls well there.. Happens automatically..

This could easily be explained by one OS considering a link local address to be a valid gateway and other considering it to be invalid. If the relevant RFC says it is invalid, then the RA packet shouldn't have looked like that in the first place, in which case which of the two behaviours the client OS should use is entirely a matter of taste.