Re: [Asrg] reject and DSN, was What are the IPs

Ian Eiloart <iane@sussex.ac.uk> Thu, 02 July 2009 09:17 UTC

Return-Path: <iane@sussex.ac.uk>
X-Original-To: asrg@core3.amsl.com
Delivered-To: asrg@core3.amsl.com
Received: from localhost (localhost [127.0.0.1]) by core3.amsl.com (Postfix) with ESMTP id ED89C3A6837 for <asrg@core3.amsl.com>; Thu, 2 Jul 2009 02:17:45 -0700 (PDT)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -2.488
X-Spam-Level:
X-Spam-Status: No, score=-2.488 tagged_above=-999 required=5 tests=[AWL=0.111, BAYES_00=-2.599]
Received: from mail.ietf.org ([64.170.98.32]) by localhost (core3.amsl.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id KxZJ-HOIMxG9 for <asrg@core3.amsl.com>; Thu, 2 Jul 2009 02:17:45 -0700 (PDT)
Received: from karpinski.uscs.susx.ac.uk (karpinski.uscs.susx.ac.uk [139.184.14.85]) by core3.amsl.com (Postfix) with ESMTP id DDB273A6B33 for <asrg@irtf.org>; Thu, 2 Jul 2009 02:17:43 -0700 (PDT)
Received: from seana-imac.staff.uscs.susx.ac.uk ([139.184.132.137]:57966) by karpinski.uscs.susx.ac.uk with esmtpsa (TLSv1:AES256-SHA:256) (Exim 4.64) (envelope-from <iane@sussex.ac.uk>) id KM5DVI-000B24-4D for asrg@irtf.org; Thu, 02 Jul 2009 10:18:54 +0100
Date: Thu, 02 Jul 2009 10:17:59 +0100
From: Ian Eiloart <iane@sussex.ac.uk>
Sender: iane@sussex.ac.uk
To: Anti-Spam Research Group - IRTF <asrg@irtf.org>
Message-ID: <5CAA4AF19B9260B079C95234@seana-imac.staff.uscs.susx.ac.uk>
In-Reply-To: <20090701220845.73063.qmail@simone.iecc.com>
References: <20090701220845.73063.qmail@simone.iecc.com>
Originator-Info: login-token=Mulberry:01wnzfCCvdTW0D6TNqLqI18VJ7KPQAYiWiN+c=; token_authority=support@its.sussex.ac.uk
X-Mailer: Mulberry/4.0.8 (Mac OS X)
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii; format=flowed
Content-Transfer-Encoding: 7bit
Content-Disposition: inline
X-Sussex: true
X-Sussex-transport: remote_smtp
Subject: Re: [Asrg] reject and DSN, was What are the IPs
X-BeenThere: asrg@irtf.org
X-Mailman-Version: 2.1.9
Precedence: list
Reply-To: Anti-Spam Research Group - IRTF <asrg@irtf.org>
List-Id: Anti-Spam Research Group - IRTF <asrg.irtf.org>
List-Unsubscribe: <http://www.irtf.org/mailman/listinfo/asrg>, <mailto:asrg-request@irtf.org?subject=unsubscribe>
List-Archive: <http://www.irtf.org/mail-archive/web/asrg>
List-Post: <mailto:asrg@irtf.org>
List-Help: <mailto:asrg-request@irtf.org?subject=help>
List-Subscribe: <http://www.irtf.org/mailman/listinfo/asrg>, <mailto:asrg-request@irtf.org?subject=subscribe>
X-List-Received-Date: Thu, 02 Jul 2009 09:17:46 -0000

--On 1 July 2009 22:08:45 +0000 John Levine <johnl@taugh.com> wrote:

>> But, what good reason is there for NOT using a DSN when you get an
>> SPF pass?
>
> Why should it do anything different from what it does the other 95% of
> the time?  SPF is far from universal, and a whole lot of SPF lookups
> end up saying "maybe".

You've avoided the question. SPF and DKIM are both growing quite rapidly. 
Some day, you'll get a definite answer for most of your mail. Or, perhaps 
it'll be some other sender domain authentication technology.

So, why should one NOT send a DSN when the domain is authenticated? You 
said "5xx is cheaper and less likely to cause collateral damage." Well, the 
cost is minimal, and there's some benefit when we're confident about the 
sender domain.

And, what's the risk collateral damage when the sender domain is 
authenticated? I guess there's a risk that the authentication mechanism has 
been compromised - but that's the responsibility of the domain owner, isn't 
it?


> R's,
> John
>
>
> _______________________________________________
> Asrg mailing list
> Asrg@irtf.org
> http://www.irtf.org/mailman/listinfo/asrg



-- 
Ian Eiloart
IT Services, University of Sussex
01273-873148 x3148
For new support requests, see http://www.sussex.ac.uk/its/help/