Re: [IPsec] Working Group Last Call: draft-ietf-ipsecme-esp-ah-reqts

Paul Wouters <paul@cypherpunks.ca> Tue, 04 March 2014 09:59 UTC

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Date: Tue, 4 Mar 2014 04:59:25 -0500 (EST)
From: Paul Wouters <paul@cypherpunks.ca>
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To: RJ Atkinson <rja.lists@gmail.com>
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Subject: Re: [IPsec] Working Group Last Call: draft-ietf-ipsecme-esp-ah-reqts
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On Tue, 4 Mar 2014, RJ Atkinson wrote:

>> What meaning has "protecting" those bits? Endpoint A and B protect
>> something by cryptography, but any router in the middle can't trust
>> those signatures anyway. So I don't see how AH is different from
>> ESPinUDP where you set those options in the UDP header. These are
>> not "protected" but the router can't verify the crypto anyway.
>
> At least some deployed routers in the middle in some deployments
> ARE able to validate and therefore trust the AH values (and trust
> that the IP options present were placed there by the sender).  This
> was ALWAYS something that was designed-in to AH (RFC-1826, Section 1.1).
> Some other kinds of middleboxes (e.g. some firewalls) also can do this.

I was not aware of such deployments. Thanks for the information.

Paul