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Date: Wed, 15 Nov 2017 19:52:07 +0100
From: "Jeroen" <spam@...lab.nl>
To: <john-users@...ts.openwall.com>
Subject: Re: [off-topic] Envelope sender mailinglist: DMARC errors

Off-topic but perhaps useful for readers who are not that well-known with
email issue...

Matus UHLAR - fantomas wrote:
<SNAP>
>>The mailing list sends messages to list members like if they were send
>>by the original sender. In fact it's spoofing emails.
>
>no. It's resending mails from users to members. That's not spoofing.

Hi Matus,

If my From: address is used to submit a message to an outgoing mailserver
that I didn't contact (mother.openwall.net sends the list's messages, I've
sent it to my own server), that's widely considered as email spoofing: the
Openwall mailserver != Jeroen. Perhaps you use another definition and that's
fine :)

<SNAP>
>what exactly is your problem?

Example:
- DMARC is enabled and in blocking mode for the sender's email domain.
- Provider of mailing list member uses provider that checks DMARC (e.g.
Google / Gmail, also other big ones).
- Email is dropped by Google's email server and will not be delivered to all
list member.
- Result: my message doesn't reach all list members.

A real-life example (reason for this tread):

---
This is a spf/dkim authentication-failure report for an email message
received from IP 195.42.179.200 on Tue, 14 Nov 2017 18:51:30 +0800.
Below is some detail information about this message:
 1. SPF-authenticated Identifiers: lists.openwall.com;  2.
DKIM-authenticated Identifiers: none;  3. DMARC Mechanism Check Result:
Identifier non-aligned, DMARC mechanism check failures;

For more information please check Aggregate Reports or mail to
abuse@....com.
--

>Maybe the only problem is that this list should not add [john-users] to
>subject of DKIM-signed mail modifying subject sucks anyway, filtering
should
>be done on List-ID: header

This is all irrelevant for DMARC.

Alexander mentioned that there the configuration will not be changed yet and
suggested to use an email address for posting in an email domain that is
less strict. Clear answer and a good advice for everyone with similar
issues.


Cheers,

Jeroen

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