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Re: [pcp] Server's auth policy discovery

Sam Hartman <hartmans@painless-security.com> Fri, 12 October 2012 12:09 UTC

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From: Sam Hartman <hartmans@painless-security.com>
To: Alper Yegin <alper.yegin@yegin.org>
References: <0BC19EAB-01F2-4AB9-B706-FD7C98FFAE86@yegin.org> <tsl4nm0j755.fsf@mit.edu> <5077FA0A.9030308@toshiba.co.jp> <tslzk3rj530.fsf@mit.edu> <22CCCEB5-FA7E-474A-B890-5A6EB16E44DB@yegin.org>
Date: Fri, 12 Oct 2012 08:09:40 -0400
In-Reply-To: <22CCCEB5-FA7E-474A-B890-5A6EB16E44DB@yegin.org> (Alper Yegin's message of "Fri, 12 Oct 2012 14:41:29 +0300")
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Subject: Re: [pcp] Server's auth policy discovery
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>>>>> "Alper" == Alper Yegin <alper.yegin@yegin.org> writes:

    Alper> Sam,
    Alper> On Oct 12, 2012, at 2:35 PM, Sam Hartman wrote:

>>>>>> "Yoshihiro" == Yoshihiro Ohba <yoshihiro.ohba@toshiba.co.jp> writes:
    >> 
    Yoshihiro> Is discoverying binary policy (auth
    Yoshihiro> unsupported/supported) is enough, or is discovering
    Yoshihiro> three-policy (auth unsupported/mandated/optional) needed?
    >> 
    >> I think discovering auth supported is sufficient.

    Alper> So, you suggest eliminating case 2 below?

    Alper> 1. auth not used (not supported, or disabled) 2. use of auth
    Alper> is optional (i.e., PCP Client's decision) 3. auth is
    Alper> mandatory to use

No.  I simply think that if you know whether the server supports auth
then you can avoid sending auth to a server known not to support it,
which is a problem in the PANA port sharing case.

I guess what I should have said is that  if clients who want to use auth
have a way to discover if auth is supported, then I don't think we have
any concerns.

--Sam

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