Re: [savi] More Opinions, Please - On the Protection of Unused Addresses

"Joel M. Halpern" <jmh@joelhalpern.com> Mon, 29 June 2009 23:36 UTC

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Date: Mon, 29 Jun 2009 19:36:43 -0400
From: "Joel M. Halpern" <jmh@joelhalpern.com>
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Subject: Re: [savi] More Opinions, Please - On the Protection of Unused Addresses
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While I appreciate Christian's question, I think that this is part of a 
larger pair of questions that we talk around, but do not address.

1) What threats are we actually trying to protect against.  The threats 
draft talks about general internet threats and the need to be able to 
track them back.  But it is not particularly clear about what behavioral 
threats we are actually concerned with stopping in SAVI
- Are we concerned with ensure that every packet leaving a site can be 
reliably tracked back to a human being
- Are we concerned with preventing one device within a site from 
masquerading as another device, either at the IP or MAC layer.

2) What tools do we want to require or prohibit.  While we probably do 
not want to mandate a single tool set, without mandating something we 
get nowhere.  Possibilities include
- restricting mobility (with or without session continuity)
- Requiring MAC or IP authentication (*02.1X, SEND, ...)
- Requiring central management of addressing and bindings

No, those are not all the alternatives.  As far as I can tell from 
watching this list, there are folks who take as given the need for 
almost any subset of these and related constraints you can imagine. 
Unless we pick, explicitly, we will continue to argue in circles.

For example, the question of controlling unregistered addresses turns on 
assumptions about what threats we are addressing, and assumptions about 
address allocation that mean that "unregistered" is a meaningful 
condition.  I don't object to that particular pair, but it is really 
hard to discuss the acceptability of answers without agreeing on the 
questions.

Yours,
Joel M. Halpern

Christian Vogt wrote:
> Folks -
> 
> I would like to solicit more feedback on the benefit-cost analysis
> (below) for protecting unused addresses. How valuable do people consider
> protection of unused addresses, how much cost do they think is OK?  Is
> there something that the analysis overlooks?  We already got several
> very useful comments from a few people.  What do the others think?
> 
> To recap:  We need to decide between the following three options of
> dealing with unused addresses:
> 
> - Not protect unused addresses, i.e., forward packets without a binding.
>   Logging is still possible, though.
> 
> - Protect unused addresses, and coordinate SAVI devices on the same link
>   by manually disabling SAVI protection on ports connecting to other
>   SAVI devices.
> 
> - Protect unused addresses, and coordinate SAVI devices on the same link
>   with a dedicated binding synchronization protocol.
> 
> Please send your feedback by Sunday, July 5.  We will vote after that.
> 
> - Christian

[savi] On the Protection of Unused Addresses Christian Vogt
Re: [savi] On the Protection of Unused Addresses Fred Baker
Re: [savi] On the Protection of Unused Addresses Christian Vogt
Re: [savi] On the Protection of Unused Addresses Fred Baker
Re: [savi] On the Protection of Unused Addresses Greg Daley
[savi] More Opinions, Please - On the Protection … Christian Vogt
Re: [savi] On the Protection of Unused Addresses Christian Vogt
Re: [savi] More Opinions, Please - On the Protect… Joel M. Halpern
Re: [savi] More Opinions, Please - On the Protect… Christian Vogt
Re: [savi] More Opinions, Please - On the Protect… Christian Vogt
Re: [savi] On the Protection of Unused Addresses marcelo bagnulo braun
Re: [savi] More Opinions, Please - On the Protect… marcelo bagnulo braun
Re: [savi] More Opinions, Please - On the Protect… marcelo bagnulo braun
Re: [savi] On the Protection of Unused Addresses Christian Vogt
Re: [savi] On the Protection of Unused Addresses Christian Vogt
Re: [savi] On the Protection of Unused Addresses marcelo bagnulo braun
Re: [savi] On the Protection of Unused Addresses marcelo bagnulo braun
[savi] Using shared secrets to identify other SAV… Christian Vogt
Re: [savi] On the Protection of Unused Addresses Christian Vogt
Re: [savi] Using shared secrets to identify other… marcelo bagnulo braun
Re: [savi] Using shared secrets to identify other… Greg Daley
Re: [savi] Using shared secrets to identify other… Christian Vogt