PMG changes original message

[viatcheslavkvv]

Hi!
The situation is as follows.
I use PMG as a gateway between the Internet and the target mail server (Zimbra). I got incoming emails from some domains appeared in spam (not ProxMox, but Zimbra spam) due to a DKIM signature verification error on the target mail server (dkim=fail (1024-bit key) reason="fail (body has been altered)"). As I understand Zimbra rewrites X-Spam by itself and supposes the original message was changed. Is it possible to resolve this situation? Here is an example:

X-Spam-Flag: YES
X-Spam-Score: 9.516
X-Spam-Level: *********
X-Spam-Status: Yes, score=9.516 required=6.6 tests=[BAYES_00=-1.9,
DKIM_INVALID=0.1, DKIM_SIGNED=0.1, DMARC_FAIL_REJECT=9,
HTML_IMAGE_ONLY_20=1.546, HTML_MESSAGE=0.001,
RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H2=-0.001,
RCVD_IN_ZEN_BLOCKED_OPENDNS=0.001, SPF_HELO_NONE=0.001,
SPF_SOFTFAIL=0.665, T_REMOTE_IMAGE=0.01, T_SCC_BODY_TEXT_LINE=-0.01,
URIBL_BLOCKED=0.001, URIBL_DBL_BLOCKED_OPENDNS=0.001,
URIBL_ZEN_BLOCKED_OPENDNS=0.001] autolearn=no autolearn_force=no
Authentication-Results: receiver.com (amavisd-new);
dkim=fail (1024-bit key) reason="fail (body has been altered)"
header.d=sender.com

..........................................


DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed;
d=sender.com; s=google; t=1692347320; x=1692952120;
h=cc:to:subject:message-id:date:from:mime-version:from:to:cc:subject
:date:message-id:reply-to;
bh=HlSlzL7qYVsxZ7Oe+yiwMVPsndFVJRkJ5QjOmBut730
b=ECCz+lNNklgkg0aT895IZnkNOMSRPiHmK9qw7dFAFDUs3WeJDNXvfPs1452227EbDG
Fr1PwIQSr+Cm+gOS3Wa+zH0fdHrzVkDcxCz5rnsWtJDirNJxrC8EyjSzGkvfgCCqwOHu
VZCUwMW8Kap/Ta99WgwcToL4yWPKDmL1REcYY=
X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed;
d=1e100.net; s=20221208; t=1692347320; x=1692952120;
h=cc:to:subject:message-id:date:from:mime-version:x-gm-message-state
:from:to:cc:subject:date:message-id:reply-to;
bh=HlSlzL7qYVsxZ7Oe+yiwMVPsndFVJRkJ5QjOmBut730
b=gr2KZBGc9HSGxNdcG4Nmc8v4WSb2vuB2lv3PzOvQJ46YFfIx4U68yCjKYjd5n+HF/A
9Axeaed7KXSb2NHjRQME32CXa9Z3ydo56X+Ya1s3/vbkAQ+9bUzxQOiwYmc6edmtxW2E
9n0api7RtijwyJOoDOGSF0kcntur3/UbuC4aSjA96GtIdWB216B9xBIcxtLz3MBGjHyt
g96wKHjNCKNvpnOFtRf17eUPdJJNsQj4PadtGOZVOtsQAhBtIvfJMWDjxxnoPVvvjyxi
bg2v5q2cerPzPQfwGM1aGsBaYrmB4wURhkCHcsYUWT1TkdOl5llBKaUzWl4UXjUfcjjR
oLUQ==

Thanks in advance,
Viatcheslav

 

[viatcheslavkvv]

Maybe I didn't phrase it well. As I understand, Zimbra thinks, that PMG has changed the original message. It seems to be true, but I steel haven't found real part had been changed.

 

[Stoiko Ivanov]

One option to get more info for this would be to send a mail to 2 recipient (one behind PMG, one directly) - and compare the .eml files
Else it's hard to find the actual reason.

PMG does parse the mails and then writes out the parsed version - so in theory something could change that renders DKIM signatures invalid - however this happens really seldomly.

 

[viatcheslavkvv]

Thank you! I have such situation with a couple of correspondents only. So I'll try to ask them to send CC to non-PMG address.