[CentOS] mailing list mail from @yahoo addresses

[extracted from "Re: [CentOS] dnf and failing epel" message chain.]


> From: lejeczek peljasz at yahoo.co.uk
> Date: Fri Nov 4 13:39:40 UTC 2016

>> Date: Friday, November 04, 2016 08:51:07 -0400
>> From: Jonathan Billings <billings at negate.org>
>>
>>> On Fri, Nov 04, 2016 at 12:30:02PM +0000, lejeczek wrote:
>>>
>>> ps. I wonder if my email get though to the group, I receive
>>> mailing list emails but I don't get my own emails?
>>
>> You can sign into this URL:
>> 
>> https://lists.centos.org/mailman/listinfo/centos
>>
>> ... and change the settings.  One of the settings is whether to
>> "Receive your own posts to the list".  Make sure it is marked as
>> "yes".
>
> it's been there always.
> Some mailing lists I do have this problem with, others work 
> fine, and it's not the settings reason, certainly not that 
> one setting and rest looks ok too.
> I wonder if Centos mailman uses some blocking/blacklisting? 
> But then why the group gets my emails but me?

I believe that the issue is that yahoo updated their dmarc record a
bit ago, so now won't accept mail, from 3rd-parties, that has an
@yahoo... "mailfrom", as yours do on this list.

If the non- at yahoo mailing sender doesn't do what's necessary to deal
with enforced dmarc, and your mail provider enforces dmarc, you won't
see messages from @yahoo correspondents -- which is likely why you
aren't seeing your own list messages. Additionally if a mailing list
has enough @yahoo posters, this can generate sufficient bounces to
get you kicked off the mailing list on a regular basis.

There are various ways for mailers/mailing lists to deal with the
enforced dmarc. My understanding is that with Mailman, which this
list uses, one has to upgrade to -3.


  Email service providers can't send to/from Yahoo Mail addresses

  Questions about our DMARC policy
  Why are my emails bouncing?

  We've updated the DMARC record with "p=reject" for multiple
  Yahoo domains.

  This means all DMARC compliant mail receivers (including Yahoo, 
  Hotmail, and Gmail) are now bouncing emails sent as "@yahoo.com" 
  addresses that aren't sent through Yahoo servers. Any messages 
  without a proper Domain Keys Identified Mail (DKIM) signature or 
  Sender Policy Framework (SPF) alignment will be rejected.

<https://help.yahoo.com/kb/SLN24016.html>

<https://yahoomail.tumblr.com/post/82426900353/yahoo-dmarc-policy-change-what-should-senders#_=_>