Re: A simple question

On Sun, 20 Apr 2003 03:41:37 +0700, Robert Elz said:

> Is not true for site locals, as no-one anticpiates that a SL address is
> all an enterprise will be using (unless it is not connected to the
> internet, in which case questions of its flexibility of access don't arise).
>
> For internet access, a global address is used.   Sites (and hosts) have both.
So if it's expected that both global and site-local addresses are available,
why are we bothering with making things more complicated?

> Similarly:
>
>   |    Once one commits to using a private address, one is committing to
>   |    renumber part or all of an enterprise,
>
> is not true of SL addresses, as one doesn't "renumber" them, one just
> augments with a global address.
That's exactly *why* they're broken - if you've suddenly had a global
address show up, there's now a danger of leaking a local address, so it's
not safe to use site-local anymore.


>   | I'm afraid that unless site-local includes a 'MUST renumber' requirement
>   | for *BOTH* cases, it's a complete and total non-starter in my book.
>
> IPv6 requires renumbering when an address that has been used is no longer
> appropriate (which will generally be because of changed topology, which
> may be local topology changes - moving a host to a different LAN, or global
> ones - connecting to a different provider).   That is the only reason.
> As long as prefixes remain usable, they can keep on being used, with other
> prefixes added as required.
Well.. all you need to do to fix this is to make a rule that if a
global prefix becomes available, the site-local prefix is no longer
appropriate and must be withdrawn.

This *still* leaves the problem of using site-local behind a NAT, though.

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