Re: Why ULA: low collision chance (Was: IPv6 fc00::/7 — Unique local addresses)

[Joel Jaeggli <joelja () bogus com>]

On 10/21/10 6:02 AM, William Herrin wrote:
> On Thu, Oct 21, 2010 at 8:14 AM, Ray Soucy <rps () maine edu> wrote:
> > That's assuming ULA would be the primary addressing scheme used.  If
> > that became the norm, I agree, the extra uniqueness would be
> > desirable, perhaps to the point that you should be asking an authority
> > for FC00::/8 space to be assigned.  But then why wouldn't you just ask
> > for a GUA at that point.
>
> Because you might want space that doesn't route on the Internet so
> that if your routes accidentally leak external folks still can't reach
> you?

Announce your gua and then blackhole it and monitor your prefix. you can
tell if you're leaking. it's generally pretty hard to tell if you're
leaking rfc 1918 since your advertisement may well work depending on the
filters of your peers but not very far.

> Regards,
> Bill Herrin