Re: Comments on draft-wbeebee-ipv6-cpe-router-01.txt

[Gert Doering <gert@space.net>]

Hi,

On Mon, Jul 21, 2008 at 07:31:58AM -0400, Hemant Singh (shemant) wrote:
> > - false: you need a global address on the WAN interface for uRPF
> 
> If you don't see the obvious problem with uRPF with just a link-local
> address on the WAN interface, I suggest you go do a test and get back to
> us.

Whether or not a specific *implementation* fails with this has nothing
to do whatsoever with "obvious problems".

There is no fundamental problem with uRPF over "unnumbered" interfaces
(be it link-local or explicitely configured as "ipv6 unnumbered <other>").

The example that you have given ("default route is special") is fairly
irrelevant - because it's still special, even if you have a global IPv6
address on the WAN interface.  So you if you do uRPF without a default
route, you will still not be able to receive packets "from the world" - 
you'll be able to receive packets from connected neighbours, and 
nothing else.  Which isn't overly useful.

Gert Doering
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