> Date: Saturday, June 16, 2018 05:25:05 -0500
> From: Johnny Hughes via CentOS <centos@xxxxxxxxxx>
>
> On 06/15/2018 05:18 PM, Richard wrote:
>>
>>
>> I believe this is a DMARC issue. Yahoo, among other places, has set
>> their dmarc records to p=reject:
>>
>> dig +short txt _dmarc.yahoo.com
>> "v=DMARC1; p=reject; pct=100; rua=mailto:dmarc_y_rua@xxxxxxxxx;";
>>
>> So, if your mail hosting provider enforces dmarc,(gmail does) and
>> you get mail from a list that doesn't rewrite the headers, and
>> people from places like yahoo post to the list, you'll likely get
>> some form of warning about being being kicked off the mailing list
>> every now and then. The frequency depends on how often people from
>> p=reject places post, and what the settings are for bounce
>> handling of the mailing list in question.
>>
>> I believe that the current version of mailman can be configured to
>> do the necessary header rewrites. Some lists I'm on only do the
>> rewrites for headers of posts coming from p=reject sites (much
>> less annoying than having them all rewritten).
>
> This is indeed what happened. An email from yahoo.com.uk caused
> gmail to reject all the mails sent by that user because of the
> yahoo DMARC settings.
>
> We have now set the mailing list to rewrite headers. That also has
> set the From: of the email to the Mailing list and not the Original
> Author. The author is moved to the CC: block and you can still
> easily see who sent it and my email client (thunderbird) still does
> things the same way (reply to list sends to the list, reply sends
> to the original author).
>
> This should prevent the yahoo/gmail (or other dmarc) issues from
> happening again.
>
> For others running mailings lists on CentOS with this issue, Red
> Hat has back ported the 'dmarc_moderation_action' into the current
> version of mailman that is used in RHEL and CentOS. You can follow
> the instructions here for Mailman 2 (for version 2.1.18) even
> though the version in CentOS is mailman-2.1.15-26.el7_4.1
>
> we will be watching the list for the next few days to see if this
> change is working as expected. If it id not working for other
> email clients please let us know.
>
> Great job by Brian Stinson to figure all this out :)
>
> Thanks,
> Johnny Hughes
>
Thank you - one less list I'll get kicked off of regularly.
One note, I am seeing the author in the Reply-To: in the message
headers, not in the visible Cc: as you indicate:
From: Johnny Hughes via CentOS <centos@xxxxxxxxxx>
Reply-To: Johnny Hughes <johnny@xxxxxxxxxx>,
CentOS mailing list <centos@xxxxxxxxxx>
so to see the address of the sender I have to either poke through the
headers or initiate a reply. I don't think that this is email client
specific.
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