NB> "Your browser has real working IPv6 address - but is avoiding using NB> it. We're concerned about this." and..
NB> "It appears that you use a tunnel mechanism for either IPv4 or IPv6."
NB> The second one is obvious. The first one I can't seem to change in Firefox. NB> Apparantly Firefox decides that it prefers to use IPv4 instead of IPv6. NB> Isn't it supposed to try IPv6 first and fall back to IPv4 if the first try NB> doesn't work?
That's how my FireFox does it: Use IPv6 first...
NB> It seems they're saying both Chrome and Firefox do this as they NB> should, and that it's pretty much normal..
Don't think so. Are you using (one of) the latest FireFox version(s)?
Or maybe your OS does it that way? And FireFox uses just an OS Library function?