[Mailman-Users] Emails from yahoo members, are getting rejected by yahoo, "Service Unavailable".

[Jim Popovitch]

On Tue, Apr 15, 2014 at 2:05 PM, Lindsay Haisley <fmouse at fmp.com> wrote:
> On Tue, 2014-04-15 at 12:38 -0400, Jim Popovitch wrote:
>> Just to be clear, all those domains (other than yahoo.com) will bounce
>> email to you if your list sends out an email from a yahoo.com
>> subscriber.  It's not the case that you need to prevent all those
>> other domains (AOL/MSN/etc) from posting, just don't allow yahoo.com
>> addresses to post to the list.
>
> So just to be clear, putting a damper on this at this point requires
> _only_ that posts from yahoo.com be blocked from posting to a list.  Is
> this correct?  This can be done by selectively unsubscribing (or
> moderating) current yahoo.com users and adding "^.*@yahoo\.com" to the
> ban_list of addresses banned from membership going forward.  Should some
> other ESP start publishing advisory DMARC records then said ESP would
> need to be added to the ban_list as well.
>
> Am I correct in this?

You don't need to ban yahoo members, you just most likely don't want
them posting.

As of right now, today, you should prevent yahoo.com addrs from
posting to your lists.  Of course that could all change tomorrow if
Hotmail published a dmarc p=reject record.  However, given the yahoo
fallout, I think it will be a while before we see anymore of this
kinds of shenanigans.  I'm still predicting that yahoo pulls their
dmarc record (unless of course they are getting out of the end-user
email biz)

-Jim P.