Issue Multiple DKIM-Signatures per Mail (when using mailman)

[Jan]

Hei,
I've some issues with DKIM-Signatures appearing multiple times.
Any ideas?

Thanks, Jan

PRODUCT, VERSION, OPERATING SYSTEM, ARCHITECTURE
Plesk Onyx
Version 17.0.17 Update #15, last updated on Feb 1, 2017 06:27 AM
‪Debian 8.7‬, amd64

PROBLEM DESCRIPTION
DKIM-Signatures are included dozens of times, when mailman forwards mail.
The number of signatures (> 20) roughly correlates with the numbers of subscribes (30), but it differs (due to churn?)

STEPS TO REPRODUCE
Send a mail to the mailman mailinglist.

ACTUAL RESULT
(Part of a SMTP-header of a mail delivered to a lists's subscriber)

Envelope-to: [email protected]
Delivery-date: Fri, 10 Feb 2017 07:23:45 +0100
Received: from www6.jluehr.de ([82.165.61.77] helo=plesk.jluehr.de)
   by mx.jluehr.de with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256)
   (Exim 4.84_2)
   (envelope-from <[email protected]>)
   id 1cc4cS-0004Fh-Lb
   for [email protected]; Fri, 10 Feb 2017 07:23:45 +0100
Received: from plesk.jluehr.de (localhost [IPv6:::1])
   by plesk.jluehr.de (Postfix) with ESMTP id 7A2FF1A06B9;
   Fri, 10 Feb 2017 07:21:42 +0100 (CET)
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=crypto.koeln;
   s=default; t=1486707702;
   bh=vqtdlDDv2DYAfY0xRPzW/X9pFN4QCw85PcAQT2o5ENw=; l=2636;
   h=Received:Received:To:From:Subject;
   b=JuzxHfd8vC5qCdsHeJxoA0JXfrv/oc/kkkW7baMPnlbGA20i0NSXTn7EmL0UpZdLV
    Wa+LRd7iCVbdZwmn26g6x2a9Chy8GUPiOBBYd7CAxY0PquCYuv+2XiNi5absDuiP6D
    2qLUSDdmLn3qKinFN5KifqnrdAMKuAGZTSQQFARc=

(... 20 identical DKIM signatures removed due to phpbb's limit of 10000 chars)

DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=crypto.koeln;
   s=default; t=1486707702;
   bh=vqtdlDDv2DYAfY0xRPzW/X9pFN4QCw85PcAQT2o5ENw=; l=2636;
   h=Received:Received:To:From:Subject;
   b=JuzxHfd8vC5qCdsHeJxoA0JXfrv/oc/kkkW7baMPnlbGA20i0NSXTn7EmL0UpZdLV
    Wa+LRd7iCVbdZwmn26g6x2a9Chy8GUPiOBBYd7CAxY0PquCYuv+2XiNi5absDuiP6D
    2qLUSDdmLn3qKinFN5KifqnrdAMKuAGZTSQQFARc=


Received: from lists.datenschutzraum.org (lists.datenschutzraum.org
 [217.69.76.189])
 by plesk.jluehr.de (Postfix) with ESMTPS id 10F181A0642
 for <[email protected]>; Fri, 10 Feb 2017 07:21:40 +0100 (CET)

EXPECTED RESULT
(Part of a SMTP-header of a mail delivered to a lists's subscriber)

Envelope-to: [email protected]
Delivery-date: Fri, 10 Feb 2017 07:23:45 +0100
Received: from www6.jluehr.de ([82.165.61.77] helo=plesk.jluehr.de)
   by mx.jluehr.de with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256)
   (Exim 4.84_2)
   (envelope-from <[email protected]>)
   id 1cc4cS-0004Fh-Lb
   for [email protected]; Fri, 10 Feb 2017 07:23:45 +0100
Received: from plesk.jluehr.de (localhost [IPv6:::1])
   by plesk.jluehr.de (Postfix) with ESMTP id 7A2FF1A06B9;
   Fri, 10 Feb 2017 07:21:42 +0100 (CET)
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=crypto.koeln;
   s=default; t=1486707702;
   bh=vqtdlDDv2DYAfY0xRPzW/X9pFN4QCw85PcAQT2o5ENw=; l=2636;
   h=Received:Received:To:From:Subject;
   b=JuzxHfd8vC5qCdsHeJxoA0JXfrv/oc/kkkW7baMPnlbGA20i0NSXTn7EmL0UpZdLV
    Wa+LRd7iCVbdZwmn26g6x2a9Chy8GUPiOBBYd7CAxY0PquCYuv+2XiNi5absDuiP6D
    2qLUSDdmLn3qKinFN5KifqnrdAMKuAGZTSQQFARc=

Received: from lists.datenschutzraum.org (lists.datenschutzraum.org
 [217.69.76.189])
 by plesk.jluehr.de (Postfix) with ESMTPS id 10F181A0642
 for <[email protected]>; Fri, 10 Feb 2017 07:21:40 +0100 (CET)

ANY ADDITIONAL INFORMATION
None

 

[themew]

Reported back in December 2016, waiting for a fix (PPPM-5476)

Issue - 315 duplicate DKIM Signatures in one Email Header

 

[Jan]

Hei,

thanks for your feedback. There's subtle difference here: It's not the to-field; it's the envelope-to (aka rcpt to, that blows up the header.

Is there any news on the bug? This is somewhat problematic. If the lists has 1000 subscribes, ~ 385KB are added to each message. For 10000 it's ~ 3,5 MB .... boom .... this doesn't scale ...
Is there a workaround (except for disabling DKIM)?

Greetz, Jan

 

[B_P]

Hei,

thanks for your feedback. There's subtle difference here: It's not the to-field; it's the envelope-to (aka rcpt to, that blows up the header.

Is there any news on the bug? This is somewhat problematic. If the lists has 1000 subscribes, ~ 385KB are added to each message. For 10000 it's ~ 3,5 MB .... boom .... this doesn't scale ...
Is there a workaround (except for disabling DKIM)?

Greetz, Jan

In addition, this leads to the issue that many mail servers reject such messages!

 

[Jan]

Is there any news on this? Afaik a new plesk version is not availble yet. This issue - altough urgent - is rotting ...

 

[B_P]

This seems at least partly to be fixed now with Plesk 17.5 MU51: Change Log for Plesk
However, it is not clear what "domains with short names" are...?
I just tried it for one of my domains and the issue seems to be fixed. However, we need to test this for all domains still.

Still, this took quite a while! So a recommendation for the future might be to rely rather on open source tools (opendkim) and integrate them well into the Plesk chain... That might make it possible for us to solve such issues ourselves...