Re: [OT] IP address collisions (was: Accessing a host with variable IP addresses / connection types)

[Michael Stone <mstone@debian.org>]

On Wed, Apr 17, 2019 at 09:37:36PM +0200, Pascal Hambourg wrote:
> Le 17/04/2019 à 18:42, Michael Stone a écrit :
> > On Wed, Apr 17, 2019 at 12:38:11PM -0400, Celejar wrote:
> > > On Wed, 17 Apr 2019 12:10:56 -0400 Michael Stone 
> > > <mstone@debian.org> wrote:
> > >
> > > > On Wed, Apr 17, 2019 at 11:57:43AM -0400, Celejar wrote:
> > > > > I was rather shocked to see that there was no definitive solution to
> > > > > avoid address collisions
> > > >
> > > > Sure there is--globally unique IPs.
> > >
> > > I assume you're referring to IPv6? I was referring to IPv4.
> >
> > It applies to both, though we've run out of IPv4. There's no other 
> > way to guarantee the absence of network collisions.
>
> A properly generated IPv6 ULA (Unique Local Address) prefix is 
> unlikely to have collisions.

A randomly selected subnet from 10/8 is also *unlikely* to have 
collisions. But there's a defined difference between "unlikely" and 
"guaranteed".