Subject: RE: Limiting the Use of Site-Local

From: "Michel Py" <[email-masked]>
Date: Mon, 28 Oct 2002 09:25:24 -0800

Margaret,

> Besides, it would be possible (although perhaps not
> adviseable) to enforce this restriction.  Nodes could
> immediately deprecate site-local addresses whenever a
> global address is configured.

I think this is a terrible idea. I can envision many situations where a
host would need both a site-local and a global address.

> In fact, I am suggesting that all routers and hosts treat
> site-local unicast addresses exactly like global unicast
> addresses, and that we administratively restrict the use
> of site-local unicast addresses to non-globally-connected
> networks.

I am comfortable with this. It's roughly what we do with RFC1918
addresses today, and it has worked fine for many people. Link-locals are
not routable, but site-locals are within the site, and since hopefully
nobody will invent IPv6 NAT, filtering site-local addresses at the edge
of the site seems the appropriate solution to me.

My $0.02

Michel.

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From: Keith Moore <[email-masked]>
Date: Mon, 28 Oct 2002 13:21:21 -0500

> host would need both a site-local and a global address.

please, elaborate.  I haven't seen a good one yet.

> addresses today, and it has worked fine for many people. 

YES, this is what RFC 1918 _says_ - those addresses are for isolated
networks only.  And had those restrictions been adhered to I agree
it would have worked fine for most people.

NO, it's not roughly what we do with RFC 1918 addresses today - 
roughly what we do with them to day is use them as local addresses
behind a NAT - a usage which is NOT consistent with RFC 1918 and 
which has caused huge problems.

NO, this has not worked fine for many people - it's broken a 
large number of applications, and it has had a adverse effect on 
the network's ability to support apps.

> Link-locals are

you're missing the burden that having a mixture of SLs and globals
puts on apps.

Keith