Re: [Int-area] AD evaluation: draft-ietf-intarea-nat-reveal-analysis

[Joe Touch <[e-mail]>]

On 2/11/2013 4:08 PM, Suresh Krishnan wrote:
> Hi Brian,
>    Thanks for the review. I wanted to clarify three points that you
> raised and I will ask the authors take care of the rest.
>
> On 02/11/2013 04:11 PM, Brian Haberman wrote:
>> 7. In Section 4.1.2, it would be good to describe any issues that the
>> approach has with the original use of the Identification field for
>> fragmentation reassembly.  If a middlebox changes the ID field, weird
>> things can/will happen if those packets are fragmented somewhere.
>
> Agree. I think this is precisely the reason that the mechanism for
> putting the HOST_ID in the IP-ID is a non-starter.

It happens if the packet is fragmented before the middlebox (reusing the 
HOST_ID will destroy the reassembly if any fragment groups are 
interleaved), or after (if there are multiple paths and not all 
fragments go through the middlebox.

It also violates RFC6864 if the packets are already fragmented when they 
go through the middlebox translation.

Joe