[secdir] SECDIR review of draft-kucherawy-authres-vbr

David McGrew <mcgrew@cisco.com> Thu, 06 January 2011 15:56 UTC

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From: David McGrew <mcgrew@cisco.com>
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Date: Thu, 6 Jan 2011 07:58:18 -0800
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Subject: [secdir] SECDIR review of draft-kucherawy-authres-vbr
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I have reviewed this document as part of the security directorate's  
ongoing effort to review all IETF documents being processed by the  
IESG.  These comments were written primarily for the benefit of the  
security area directors.  Document editors and WG chairs should treat  
these comments just like any other last call comments.

This draft defines a way that a border mail gateway that assesses  
inbound email using VBR can use AUTHRES to pass along the results of  
its assessment to user agents or other entities such as mail filters.   
This is a sensible and useful thing to do, and the draft is  
straightforward and clear.  I have a few comments/questions.

Section 1.  It is not clear what problem is referred to in paragraph  

Section 4.

What behavior should a mail filter have upon receiving the result  
codes defined in that section?   If the recommended behavior is  
defined elsewhere (presumably [VBR]), then it should be referenced in  
this section.

What behavior should a border mail gateway have upon receiving a VBR  
response?   For instance, under what conditions (if any) should a  
border mail gateway not forward an email on which VBR has returned  
"fail"?   I would guess that this draft expects gateways to always  
forward emails, and regards a mail filter as a logically separate  
entity.  I suggest clarifying this point.

Section 6.  The Security Considerations are short, but I agree with  
what they say (that the Security Considerations of [VBR] and [AUTHRES]  
should be read and understood).