[arin-ppml] Draft Policy 2011-5: Shared Transition Space for IPv4 Address Extension - IAB comment

[Joel Jaeggli]

On Jun 28, 2011, at 8:48 AM, William Herrin wrote:

> On Tue, Jun 28, 2011 at 10:50 AM, Joel Jaeggli <joelja at bogus.com> wrote:
>> On Jun 28, 2011, at 5:50 AM, Jimmy Hess wrote:
>>> On Tue, Jun 28, 2011 at 1:43 AM, Joel Jaeggli <joelja at bogus.com> wrote:
>>>> On Jun 27, 2011, at 11:24 PM, Benson Schliesser wrote:
>>>>> On Jun 28, 2011, at 0:25, David Kessens <david.kessens at nsn.com> wrote:
>>>> It's new private scope v4 address space carved out of ipv4 unicast space. by definition it breaks assumptions that existing hosts and applications make about non-rfc-1918 space.
>>>> 
>>> [snip]
>>> 
>>> What assumptions would those be?
>> 
>> That a port mapped to a the outside of a cpe which does not
>> have an rfc 1918 address will in fact be reachable (example
>> by upnp or nat pmp)
> 
> That's ASS-U-ME assumption. Lots of places uses non-RFC1918 addresses
> inside their NATs and those which don't often have other forms of
> filtering and firewalling which obstruct global reachability inbound.

we're not talking about lots of places. we're talking specifically about the behavior of residential CPE, which this prefix assignment is proposed to address.

> You can only assume the opposite - that a port mapped on an RFC1918
> address won't be globally reachable. Nothing in proposal 2011-5 breaks
> that assumption.

it creates an new address range which is not addressed in existing CPE and fundamentally this prefix is about not colliding with the behavior of existing cpe.

>> That an ipv4 unicast address can be used as source or
>> destination for an auto-tunneling mechanism.
> 
> And again.
> 
> 
>> Aa specific example of the later with an rfc-1918 address
>> assignment an existing implmentation of 6to4 will simply
>> fail, which is the desired behavior
> 
> No, actually, it is not the desired behavior, at least not by me. In
> fact, it obstructs the use of 6to4 on private networks where it could
> otherwise facilitate a staged IPv6 rollout.

It is the behavior defined in rfc 3056/3068 more to the point existing cpe that implement 6to4 generally honor this.


> I ran in to this, much to
> my frustration, back when I was tinkering with 6to4.

> If there's a case where a device or protocol should make positive
> assumptions about global reachability based on its assigned IP
> address, I haven't heard it yet.
> 
> Regards,
> Bill Herrin
> 
> 
> -- 
> William D. Herrin ................ herrin at dirtside.com  bill at herrin.us
> 3005 Crane Dr. ...................... Web: <http://bill.herrin.us/>
> Falls Church, VA 22042-3004
>