IETF Logo Mail Archive

Re: [Asrg] misconception in SPF

Martijn Grooten <martijn.grooten@virusbtn.com> Sun, 09 December 2012 16:13 UTC

Return-Path: <martijn.grooten@virusbtn.com>
X-Original-To: asrg@ietfa.amsl.com
Delivered-To: asrg@ietfa.amsl.com
Received: from localhost (localhost [127.0.0.1]) by ietfa.amsl.com (Postfix) with ESMTP id EF4E021F8C08 for <asrg@ietfa.amsl.com>; Sun, 9 Dec 2012 08:13:37 -0800 (PST)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -8.74
X-Spam-Level:
X-Spam-Status: No, score=-8.74 tagged_above=-999 required=5 tests=[BAYES_20=-0.74, RCVD_IN_DNSWL_HI=-8]
Received: from mail.ietf.org ([64.170.98.30]) by localhost (ietfa.amsl.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id mFofgV-gOcdf for <asrg@ietfa.amsl.com>; Sun, 9 Dec 2012 08:13:37 -0800 (PST)
Received: from mx6.sophos.com (mx6.sophos.com [195.171.192.176]) by ietfa.amsl.com (Postfix) with ESMTP id 4DAB721F8BE2 for <asrg@irtf.org>; Sun, 9 Dec 2012 08:13:37 -0800 (PST)
Received: from mx6.sophos.com (localhost.localdomain [127.0.0.1]) by localhost (Postfix) with SMTP id DCF9375192B for <asrg@irtf.org>; Sun, 9 Dec 2012 16:13:32 +0000 (GMT)
Received: from abn-exch1b.green.sophos (unknown [10.100.70.62]) by mx6.sophos.com (Postfix) with ESMTPS id B114D751910 for <asrg@irtf.org>; Sun, 9 Dec 2012 16:13:32 +0000 (GMT)
Received: from ABN-EXCH1A.green.sophos ([fe80::67:3150:dacd:910d]) by abn-exch1b.green.sophos ([fe80::dc96:facf:3d2c:c352%17]) with mapi id 14.02.0247.003; Sun, 9 Dec 2012 16:13:32 +0000
From: Martijn Grooten <martijn.grooten@virusbtn.com>
To: Anti-Spam Research Group - IRTF <asrg@irtf.org>
Thread-Topic: [Asrg] misconception in SPF
Thread-Index: AQHN0+ufsqH0dJXpZk22wCV06nTFZ5gMNOaAgAASggCAALs6AIADkeEAgAALbQCAAAOZCg==
Date: Sun, 09 Dec 2012 16:13:31 +0000
Message-ID: <0D79787962F6AE4B84B2CC41FC957D0B20ACE6D0@ABN-EXCH1A.green.sophos>
References: <20121206212116.10328.qmail@joyce.lan> <50C1A95A.5000001@pscs.co.uk> <50C4A7F8.3010201@dcrocker.net>, <CAFdugamTbTirVV2zXKOmc9oTaCS+QiTemhT=jvYJnHYscHQK7g@mail.gmail.com>
In-Reply-To: <CAFdugamTbTirVV2zXKOmc9oTaCS+QiTemhT=jvYJnHYscHQK7g@mail.gmail.com>
Accept-Language: en-GB, en-US
Content-Language: en-GB
X-MS-Has-Attach:
X-MS-TNEF-Correlator:
x-originating-ip: [10.100.64.11]
Content-Type: text/plain; charset="us-ascii"
Content-Transfer-Encoding: quoted-printable
MIME-Version: 1.0
Subject: Re: [Asrg] misconception in SPF
X-BeenThere: asrg@irtf.org
X-Mailman-Version: 2.1.12
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/options/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: Sun, 09 Dec 2012 16:13:38 -0000

> a forged email pass anyway

A forged email using a subdomain for which no SPF record exists will pass the test checks against SPF fails, something which some spam-filters include, as it's a cheap way to get rid of a chunk of spam. Such a forged email will NOT "pass" SPF.

It is in theory possible that there is a incorrectly configured spam-filter out there that gives you an easy ride if you use an SPF-less subdomain in the SMTP envelope. I doubt this is the case, but if it does exist, please do tell its developers to fix their filter.

> I think is a misunderstanding of a huge part
> of the operators

Is it? Have you evidence, even if it is only anecdotal, that such a misunderstanding exists?

If so, as Dave said, we should consider writing better documentation.

Martijn.

________________________________

Virus Bulletin Ltd, The Pentagon, Abingdon, OX14 3YP, England.
Company Reg No: 2388295. VAT Reg No: GB 532 5598 33.

v2.23.0 | Report a Bug | By Email