>> Great idea, ULAs. > > In the right circumstances, yes, actually. And actually my circumstances > yesterday were right for a ULA prefix: the ISP failed to give my CE a prefix. > Today, they gave me a prefix, and so Linux gives me a default route. Hmm, what's so bad with still using the global prefix until the global connectivity comes back and the CPE gets a new one? Than it's early enough to set the preferred time of the former prefix to 0 and let them time out. In this way all local communication will not be interrupted if your Internet connection fails.
And sending the old prefix as a hint in the DHCPv6-PD reqest let a chance open to get the same prefix again. Then local communication will not be affected by the upstream failure at all. Of course the default route should *not* be withdrawn.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". BR Holger
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