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

[Robert Heller]

At Wed, 24 Aug 2016 14:24:32 -0500 (CDT) Ted Hatfield <ted at io-tx.com> wrote:

> 
> On Wed, 24 Aug 2016, Mark Sapiro wrote:
> 
> > On 08/23/2016 03:55 PM, Ted Hatfield wrote:
> >>
> >> 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 address.
> >
> >
> > Don't munge 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 result.
> >
> >
> > No. Based on AOL's reply above, this has nothing to do with DMARC. If
> > you set reply_goes_to_list to This list (note that Poster is the
> > /strongly/ recommended setting) both the To: and Reply-To: headers of
> > outgoing messages will contain the list address.
> >
> > However, it seems that this means AOL will not accept mail from any list
> > with reply_goes_to_list = This list, and since this is a common,
> > although not recommended, configuration, if this is the case, it seems
> > there should be much more reports of this issue, and I haven't seen that.
> >
> >
> >> 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?
> >
> >
> > Even if this is a DMARC issue, Wrap message won't change it because the
> > headers in the wrapper will be the same as those in a Munge from message.
> >
> >
> >> Is there a recommended policy regarding this issue?
> >
> >
> > Set reply_goes_to_list to Poster
> >
> > --
> 
> I'm running mailman version 2.1.22.
> 
> reply_goes_to_list is set to poster
> 
> from_is_list is set to "Munge From".
> 
> Documentation describes "Munge From" to be
> 
> "This action replaces the poster's address in the From: header with the 
> list's posting address and adds the poster's address to the addresses in 
> the original Reply-To: header."
> 
> 
> This means that messages with a munged From: header should pass dmarc 
> checks but the senders address will be added to the reply-to header.  Does 
> this not mean that the Reply-To: and the To: address will be the same for 
> some users?

The Reply-To: and To: would be the same if those users send the post to
themselves and CC it to the list. This is *probably* unlikely, but possible I
guess.  *Normally* a user posts *To* the list (To: list address), and CC's to 
themselves (Cc: the poster).  Mailman sets the Reply-To: field to the poster's 
address and replaces the From: header to be from the list:

   To: list
   Reply-To: poster
   Cc: poster
   From: list

> 
> Ted Hatfield
> 
> 
> 
> 
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>                                                

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