On 14/10/2016 23:32, Gert Doering wrote: > Hi, > > On Fri, Oct 14, 2016 at 12:00:04PM +0200, Holger Zuleger wrote: >> Of course the default route should *not* be withdrawn. >> The RA default router announcement says just, "Hey hosts, I'm the way >> out of your local subnet", and not "Hey host, I have a upstream >> connection to the rest of the internet". > > If the router has no default route, it should not announce one - this > is why PIO exists for more specific info. > > Imagine a setup with *two* routers. One of them has broken Internet, > the other is working. How can the hosts decide if both keep announcing > themselves as "I can reach anything"?
Correct. When there's only one router, it doesn't matter too much (no default route gives a prompt fail and a broken default route turns the Internet into a black hole). But when there are multiple exits... I really should have figured this out without help. S***, it's exactly the problem that https://tools.ietf.org/html/draft-ietf-6man-multi-homed-host is aimed at. Brian