Re: IPv6 fc00::/7 — Unique local addresses

[Ray Soucy <rps () maine edu>]

I guess my point is that as soon as you introduced the human element
into ULA with no accountability, it became a lost cause.  People can't
be trusted to respect the RFC once they know it's non-routed address
space, and I suspect most won't.  Just like countless vendors still
use 1.1.1.1 as a baked-in management address even though there was
never a time when that was allowed.  It was a nice idea, but as soon
as you let people "choose" the "random" number, well... there you go.
At least if you stay within the FD space we have a chance at using FC
correctly.

On Thu, Oct 21, 2010 at 7:47 AM, Owen DeLong <owen () delong com> wrote:
> On Oct 21, 2010, at 4:33 AM, Ray Soucy wrote:
>
> > For for all intents and purposes if you're looking for RFC1918 style
> > space in IPv6 you should consider the block FD00::/8 not FC00::/7 as
> > the FC00::/8 space is reserved in ULA for assignment by a central
> > authority (who knows why, but with that much address space nobody
> > really cares).
> >
> > People may throw a fit at this, but as far as I'm concerned FD00::/8
> > will never leave the edge of our network (we null route ULA space
> > before it can leak out, just like you would with RFC1918 space).  So
> > you can pretty much use it has you see fit.  If you want to keep your
> > ULA space short there is nothing stopping you from using something
> > like FD00::1 as a valid address.
> I have no problem with that. My concern is that people will use FD00::/8
> space in OTHER ways, and, since it has potential uniqueness if you
> follow the RFC, it has greater potential for undesired success than
> RFC-1918.
>
> > You could embed your ASN into it or some other identifier if you want
> > to avoid conflicts with other non-routed address space which should
> > never enter or leave your network from the outside, but I'm just not
> > seeing the practical application for this.
> That only avoids conflicts if everyone within the networks to which
> you may communicate uses the same system of uniqueness.
> Think beyond today to the future possibility of M&A of other companies
> also using ULA, etc.
>
> Owen
>
> > On Wed, Oct 20, 2010 at 5:48 PM, Jeroen van Aart <jeroen () mompl net> wrote:
> > > <IPv6 newbie>
> > >
> > > According to http://en.wikipedia.org/wiki/IPv6_address#Special_addresses an
> > > fc00::/7 address includes a 40-bit pseudo random number:
> > >
> > > "fc00::/7 — Unique local addresses (ULA's) are intended for local
> > > communication. They are routable only within a set of cooperating sites
> > > (analogous to the private address ranges 10/8, 172.16/12, and 192.168/16 of
> > > IPv4).[12] The addresses include a 40-bit pseudorandom number in the routing
> > > prefix intended to minimize the risk of conflicts if sites merge or packets
> > > are misrouted into the Internet. Despite the restricted, local usage of
> > > these addresses, their address scope is global, i.e. they are expected to be
> > > globally unique."
> > >
> > > I am trying to set up a local IPv6 network and am curious why all the
> > > examples I come accross do not seem to use the 40-bit pseudorandom number?
> > > What should I do? Use something like fd00::1234, or incorporate something
> > > like the interface's MAC address into the address? It'd make the address
> > > quite unreadable though.
> > >
> > > Thanks,
> > > Jeroen
> > >
> > > --
> > > http://goldmark.org/jeff/stupid-disclaimers/
> > > http://linuxmafia.com/~rick/faq/plural-of-virus.html
> >
> >
> >
> > --
> > Ray Soucy
> >
> > Epic Communications Specialist
> >
> > Phone: +1 (207) 561-3526
> >
> > Networkmaine, a Unit of the University of Maine System
> > http://www.networkmaine.net/



-- 
Ray Soucy

Epic Communications Specialist

Phone: +1 (207) 561-3526

Networkmaine, a Unit of the University of Maine System
http://www.networkmaine.net/