Re: Possible issue with source address selection for ULAs...

[Ted Lemon <[e-mail]>]

I think it's not completely inaccurate to say that the network setup I
described is broken, but it's not completely accurate either. What I'm
describing is a situation where a perfectly valid network configuration
stopped working because of an automatic behavior that I think is also
perfectly valid. Certainly we can cure this problem by adding routing, but
that's not practicable at the moment, and I don't actually know what it
will take to get to where it is.

So given that assumption, what we are seeing here is something that
certainly could happen, and that the owner of the network might not know
how to fix. So the question I'm trying to get to is whether (a) it's worth
addressing this issue, and (b) what harm addressing it in the way I'm
suggesting might cause.

On Wed, Dec 8, 2021 at 12:38 PM Nick Hilliard <[e-mail]> wrote:

> Ted Lemon wrote on 08/12/2021 17:11:
> > I think we can take it as read that the right solution to this problem
> > is a full routing protocol on the home network.
>
> I was mid-reply on an email which pointed this out, and was stuck on how
> to suggest this without causing too much offence, so thank you for
> pre-empting  :)
>
> > However, my question is
> > about what a host can do to avoid this problem, given that there is no
> > full routing protocol running on the home network, which is a problem we
> > can't immediately solve.
>
> Couple of stream-of-consciousness thoughts:
>
> 1. your network is broken and you want to implement a protocol change in
> ipv6 as a workaround.  Well, ok.  Ultimately there's some complexity on
> your network, and this complexity has consequences.  The question is how
> to address the consequences: reconfig of the network to remove the
> multiple networks, ensuring that all networks have reachability to all
> others as appropriate, or change the underlying protocol to change how
> SAS works..
>
> Moving the mountain is rarely the best approach.
>
> 2. your proposed fix may not be a bad idea in its own right, but not
> because of the reasons that you want it.
>
> Nick
>