All true. I forgot to say that we've seen (years ago) routers than announced 2001:db8::/something, and if this were doing such a thing that could lead to this situation.
On 9 May 2016 at 18:17, Tore Anderson <[email protected]> wrote: > * Erik Kline <[email protected]> > >> If this router were to send out an RA advertising itself as a default >> router in this configuration that would probably cause the symptoms >> you're seeing. That's why I asked for a sample of any RAs seen on >> such a network. (Such a configuration would of course be broken, >> effectively requiring Happy Eyeballs to function at all.) > > Assuming the source address selection is implemented in a sane way, > just having a an IPv6 default router doesn't on its own explain the > symptoms described. IPv4 should be preferred due to the Android device's > link-local address not having the same scope as the IPv6 address of the > web site or whatever. See RFC6724 sections 5 and 6, rule 2. > > The RA would have to additionally contain a PIO with global scope, as I > understand it. Then you'd certainly get in trouble (disregarding Happy > Eyeballs). Even a ULA PIO could be problematic if Android's source > address selection algorithm isn't updated to RFC6724 defaults. RFC3484 > predates ULAs, so it treats them the same as other globally scoped > addresses. > > Tore
