If you don’t know, DKIM keys are the replacement for Yahoo!’s Domain Keys that were introduced to combat spam. Its basically a digital signature in the header of the email message to enable the mail server to determine the message source accurately.
I’ve been trying to get dkimproxy.out to work with postfix – which I’ve managed to do. The only issue is that it doesn’t seem to be signing the messages correctly – not quite sure whats wrong.
Delivered-To: xxx.xxxxx@gmail.com
Received: by 10.103.243.5 with SMTP id v5cs118747mur;
Fri, 19 Jun 2009 11:18:43 -0700 (PDT)
Received: by 10.210.30.10 with SMTP id d10mr1099509ebd.14.1245435522990;
Fri, 19 Jun 2009 11:18:42 -0700 (PDT)
Return-Path:
Received: from idpd.vm.bytemark.co.uk ([80.68.93.52])
by mx.google.com with ESMTP id 6si6760399ewy.54.2009.06.19.11.18.42;
Fri, 19 Jun 2009 11:18:42 -0700 (PDT)
Received-SPF: pass (google.com: domain of test@idontplaydarts.com designates 80.68.93.52 as permitted sender) client-ip=80.68.93.52;
Authentication-Results: mx.google.com; spf=pass (google.com: domain of test@idontplaydarts.com designates 80.68.93.52 as permitted sender) smtp.mail=test@idontplaydarts.com; dkim=neutral (bad format) header.i=test@idontplaydarts.com
Received: from localhost.localdomain (localhost.localdomain [127.0.0.1])
by idpd.vm.bytemark.co.uk (Postfix) with SMTP id 82728722DD
for
; Fri, 19 Jun 2009 19:19:01 +0100 (BST)
DKIM-Signature: v=1; a=rsa-sha1; c=relaxed; d=idontplaydarts.com; h=
subject; s=selector1; bh=uoq1oCgLlTqpdDX/iUbLy7J1Wic=; b=X6q/deT
OiqL1ea8qZiP3qsIKDmoWTdlt4Zgd36FfY3kAhLv1JZf1q6h93REQLqLl
subject: Hello world
Message-Id: <20090619181901.82728722DD@idpd.vm.bytemark.co.uk>
Date: Fri, 19 Jun 2009 19:19:01 +0100 (BST)
From: test@idontplaydarts.com
To: undisclosed-recipients:;Hey there test!!
I’ve checked the DKIM entry on the TXT records – it seems to be accurate and the encryption appears to be working (according to the mail.log output). Anyone got any ideas why I’m getting this “bad format” in the header? I’m guessing its something to do with the message header being incorrect….
So far I have:
- I tried reducing the size of the key – down to 384-bits from 1024-bit
- Changing the selector name
Any ideas anyone?
Update: So it appears that my crude method of sending emails using
telnet localhost 25
MAIL FROM:test@idontplaydarts.com
RCPT TO:xxx.xxxx@gmail.com
DATA
Subject: woot
hello world
.
Is a little crude and missing the To and From headers after the DATA – turns out you need to specify them. *doh* – Its all working fine now, just going to increase the size of the keys now back to 1024bits.