The mailing list for listmasters using Sympa

[Matt Taggart <address@concealed>]

Erik Olson writes:
> Apparently a few other people have now encountered this problem...
> 
> http://www.theregister.co.uk/2014/04/08/yahoo_breaks_every_mailing_list_in_th
> e_world_says_email_guru/

Here's a direct link to the John Levine IETF posting mentioned in the
above article

  http://www.ietf.org/mail-archive/web/ietf/current/msg87153.html

and the same thing posted to his blog

  http://jrl.guru/Email/yahoobomb.html

We (lists.riseup.net) started seeing massive amounts of bounces (tens
of thousands) due to to this, we have lots of yahoo.com subscribers and
list admins. List admins are also getting the 'XX% of your users are
bouncing' and panicing (and filing help tickets).

As recommended by the above posts, we have decided to block all posts
from yahoo.com addresses for now in order to limit the damage. Here is
the reject message we are using

  554 5.7.1 yahoo senders not allowed due to mailing list incompatible
     DMARC policy, see http://jrl.guru/Email/yahoobomb.html

We're probably going to need to do some list admin education work (help
pages explaining the problem, mail to all list admins, etc).

We are wary of doing anything like hacking the sender to jump through
hoops in order to deliver to yahoo.

-- 
Matt Taggart
address@concealed