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Re: [IPsec] Avoiding Authentication Header (AH)

Michael Richardson <mcr@sandelman.ca> Tue, 03 January 2012 04:08 UTC

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From: Michael Richardson <mcr@sandelman.ca>
To: Jack Kohn <kohn.jack@gmail.com>
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Cc: IPsec ME WG List <ipsec@ietf.org>, RJ Atkinson <rja.lists@gmail.com>
Subject: Re: [IPsec] Avoiding Authentication Header (AH)
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>>>>> "Jack" == Jack Kohn <kohn.jack@gmail.com> writes:
    Jack> We all know the different extension headers that exist in
    Jack> IPv6.

    Jack> You said AH helps in securing IPv6 extension headers. I want
    Jack> to understand which extension header did you specifically have
    Jack> in mind.

let me ask a different question:  what's the savings in obsoleting AH,
given that RFC4301 already makes it optional, and many vendors have
already implemented, tested and deployed the code?

    Jack> So, whats the *real* operational risk that youre looking at?

    Jack> AH covers the destination IP and the source IP. If somebody
    Jack> changes them, IPsec processing will fail at the SPD checks. So
    Jack> what do you gain by doing this?

    Jack> Again, whats the *real* gain that we get by AH?

AH works for multicast, and could work even when the receiver does not have
the key.  

-- 
]       He who is tired of Weird Al is tired of life!           |  firewalls  [
]   Michael Richardson, Sandelman Software Works, Ottawa, ON    |net architect[
] mcr@sandelman.ottawa.on.ca http://www.sandelman.ottawa.on.ca/ |device driver[
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