Slight rewording of the first sentence for more clarity:

In this scenario, the sum of functionality is greater than the parts - end 
hosts and intermediaries working together can better satisfy the customer's 
holistic deployment requirements (security, load balancing, auditing, etc) than 
either working in isolation and in complete distrust of the other.


-----Original Message-----
From: Brian Swander 
Sent: Thursday, January 07, 2010 9:14 AM
To: 'Stephen Kent'
Cc: ipsec@ietf.org; Russ Housley; gabriel montenegro
Subject: RE: [IPsec] Traffic visibility - consensus call

In this scenario, the sum of functionality is greater than the parts - end 
hosts and intermediaries working together can achieve better overall security 
than either working in isolation and in complete distrust of the other.

It'll be up to the individual customer on where to dial the knobs, and we 
should enable the options and make them as deployable as possible.  I.e. if 
customers really want to manage full IP address policies for who can do 
encrypted ESP, than that option should be available.   If they want good 
intermediary audit trails with a simpler intermediary config, that option needs 
to be available.  If they want best effort load balancing/WAN optimization, 
that option needs to be available.

This is no longer an either-or adversarial situation between end systems and 
intermediaries, and the intermediaries in play are not relegated to security 
intermediaries - although clearly security intermediaries are important here, 
too.

bs




-----Original Message-----
From: Stephen Kent [mailto:k...@bbn.com] 
Sent: Thursday, January 07, 2010 8:10 AM
To: Brian Swander
Cc: ipsec@ietf.org; Russ Housley; gabriel montenegro
Subject: Re: [IPsec] Traffic visibility - consensus call

At 10:17 PM +0000 1/6/10, Brian Swander wrote:
>I trust that this is a question on the sample set of requirements 
>for the scenario I sent to Paul.
>
>I use infrastructure and intermediaries terms interchangeably.
>
>The scenario I had in mind is:
>
>No heuristic support from any network infrastructure.
>
>Only limited number of legacy clients that require encryption, hence 
>they are capable of upgrading.
>Vast majority of legacy are ok with ESP-NULL.
>
>Potentially many uplevel clients that require encryption.   As on 
>the previous thread, we want to enable as many capabilities in the 
>cross product matrix as possible.  Hence it is extremely desirable 
>for uplevel to do encryption or integrity without forcing extra 
>infrastructure config.
>
>  I.e. I'd assume that managing ip addresses on all uplevel machines 
>that want to do encryption is prohibitive.

Color me confused.

It appears that the high level policy is:

        - pairs of "uplevel" (WESP-capable) machines are allowed to 
send data via encrypted SAs, and thus bypass the packet inspection 
that the intermediate systems would otherwise perform

        -  if either machine in a communicating pair is not "uplevel" 
then any SAs between them must be subject to inspection by the 
intermediate systems, and hence they are restricted to using ESP-NULL 
(or no IPsec at all).

What confuses me is how the intermediate systems will know which 
policy applies to any given traffic flow? If the intermediate systems 
have a list of IP addresses of the hosts that fall into the category 
of "allowed to encrypt traffic" that would work, but that approach 
relies on doing what you said would be prohibitive to manage. Even if 
one needs only to configure one of the addresses or authorized pairs, 
that is the same as what would be needed in my proposal, and thus is 
also viewed as too hard to manage. But what other means of informing 
the intermediate systems how to decide to treat these two different 
classes of traffic do you envision?

I hope that you're not suggesting that the answer is to rely on each 
node to behave properly and to use only the type of SA for which it 
is authorized. If we had sufficient confidence in these nodes to do 
that, we probably wouldn't need intermediate systems to perform 
packet inspection, right?

Steve

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