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

Ted Hatfield ted at io-tx.com
Tue Aug 23 18:55:42 EDT 2016

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 

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 as 
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. As 
a good mailing practice, please use a different email address for your reply-to 

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 can 
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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