[squid-users] This list generates a forward loop ...

[Matus UHLAR - fantomas]

On 20.07.17 17:16, Amos Jeffries wrote:
>Your DKIM signature covers the Subject and To headers. Any normal 
>mailing list will modify those,

I disagree - IMHO sane listservers don't modify those headers.

> so your server cannot do that on list 
>postings. Content-Type is also changed sometimes by our listserver 
>due to the list policy on binary attachments, I dont know whether 
>that is a common practice too but I suspect it might be. The others 
>should be fine AFAIK.

This is a better example. However, mailserver supporting DKIM should strip
the DKIM header if it's going to modify anything signed.
Other solution is to refuse message (when the signer domain SKIM policy is
signall).

>The other members mailserver does something unusually nasty - it 
>simply loops the message back at the list instead of bouncing with a 
>proper error to you. And since your address is still the envelope 
>sender our server rejects with that loop error bouncing back at you.

which is exactly what I have guessed :-)
And this is why header of original attached message were useful:

Received: from ScrolloutF1.linguitronics.com (203-74-122-103.HINET-IP.hinet.net [203.74.122.103])
     by lists.squid-cache.org (Postfix) with ESMTPS id 15AD7E1196
     for <squid-users at lists.squid-cache.org>; Thu, 20 Jul 2017 03:44:49 +0000 (UTC)
Received: by ScrolloutF1.linguitronics.com (Postfix, from userid 0)
     id 3xCfsX5v6DzHpF4; Thu, 20 Jul 2017 11:44:32 +0800 (CST)
Received: from 192.168.1.204 (192.168.1.204:143) by
   mailgateway.linguitronics.com with IMAP4; 20 Jul 2017 03:44:32 -0000

Received: from ScrolloutF1.linguitronics.com (unknown [192.168.1.205])
     by tw.linguitronics.com (Postfix) with ESMTP id 5A3E64023A
     for <spam at linguitronics.com>; Thu, 20 Jul 2017 11:35:56 +0800 (CST)
Received: from localhost (localhost [127.0.0.1])
     by ScrolloutF1.linguitronics.com (Postfix) with ESMTP id 3xCfgc5PKRzHr9d
     for <spam at linguitronics.com>; Thu, 20 Jul 2017 11:35:56 +0800 (CST)
Received: from ScrolloutF1.linguitronics.com ([127.0.0.1])
     by localhost (scrolloutf1.linguitronics.com [127.0.0.1]) (amavisd-new, port 10024)
     with LMTP id uAebWOExfOQd for <akong at linguitronics.com>;
     Thu, 20 Jul 2017 11:35:55 +0800 (CST)
Received: from lists.squid-cache.org (lists.squid-cache.org [104.130.201.120])
     by ScrolloutF1.linguitronics.com (Postfix) with ESMTP id 3xCfgP4p5LzHr9b
     for <akong at linguitronics.com>; Thu, 20 Jul 2017 11:35:39 +0800 (CST)

>[yes I wish our sysadmin could stop that bouncing, but the tools seem 
>to be limited].

removing akong at linguitronics.com from recipients should fix the problem.
I'm sending Cc: there so the culprit knows what to fix on their side.

-- 
Matus UHLAR - fantomas, uhlar at fantomas.sk ; http://www.fantomas.sk/
Warning: I wish NOT to receive e-mail advertising to this address.
Varovanie: na tuto adresu chcem NEDOSTAVAT akukolvek reklamnu postu.
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