[Mailman-Users] AOL rejecting connections from mailman servers for DMARC Munging.

Steve Wehr steve at tunedinweb.com
Thu Aug 25 09:01:33 EDT 2016

I recently have been fighting AOL over this exact same thing. To solve it I
contacted AOL via their postmaster page and opened a ticket. They got back
to me and said they "made some changes to their handling of mail from my IP

I had been using mailman to send to AOL users for over a decade, so I didn't
change anything in mailman. After about 2-3 weeks AOL has now stopped
rejecting mailman emails. 

In the interim, I used Mark Sapiro's script to reset the moderation bits on
all AOL users, encased in a little shell script I wrote:


# This script resets the bounce bits for certain users in ALL lists.
# Run this script as ROOT
for listname in $(ls /var/lib/mailman/lists/);
   echo Resetting bounce bits in list $listname
   # Reset bounce bits for only AOL.COM members.
   /usr/lib/mailman/bin/withlist -r reset_bounce $listname -d aol.com

Hope this is helpful.

Steve Wehr
Tunedin Web Design

-----Original Message-----
From: Mailman-Users
[mailto:mailman-users-bounces+steve=tunedinweb.com at python.org] On Behalf Of
Ted Hatfield
Sent: Tuesday, August 23, 2016 6:56 PM
To: mailman-users at python.org
Subject: [Mailman-Users] AOL rejecting connections from mailman servers for
DMARC Munging.

Hey all,

Recently my mailman server was flagged by AOL and my messages were rejected
with this error.

SMTP DATA-2 protocol error: 521 5.2.1 :  AOL will not accept delivery of
this message.

When I queried the AOL Postmaster about this issue this was my response.

Few mails from IP xxx.xxx.xxx.xx were getting rejected from one of filters
Reply-to address is same as the TO address. This is caused as one of our 
filters triggered these emails as spam. I have added protection for your IP.
a good mailing practice, please use a different email address for your

It seems to me that since dmarc munging adds the senders address to the 
reply-to header, if a user receives a copy of their own postings this is the


Can anyone else confirm that this has happened to them and if so what else
someone do except to wrap the message from senders that implement dmarc 
rejection as in dmarc_moderation_action?

Is there a recommended policy regarding this issue?

Ted Hatfield

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