[Mailman-Users] duplicates

Mark Sapiro mark at msapiro.net
Wed Oct 28 11:22:02 EDT 2015

On 10/28/2015 02:22 AM, Marco Stoecker wrote:
> I think I do now understand why duplication is happening. But have no
> idea how to avoid it. So here is how I think it happened.
> I send an email to list1 and list2
> now on my ISP there is an email forwarding from list1 at ... and list2 at ...
> to the email account mailmansrv at mydomain. So here I have 2 emails in
> that account which are both to: list1 and list2. Fetchmail now will get
> these 2 messages with to: to both lists and even postfix gets 2 messages
> with each adressed to two lists. I think this is the reason why
> duplication happens.
> But now I have no glue how to configure on the ISP side or
> postfix(relayhost) or mailman to avoid such duplicates.
> Any assistance possible here in this mailing list?

Yes. That is what's happening

To fix this, if it is possible to eliminate fetchmail and have the ISP
email forwarding go directly to your machine, you can then configure
Postfix on your machine to deliver to Mailman with aliases in the normal
way and the problem is solved.

If it is not possible to to eliminate fetchmail because, e.g., it is not
possible to mail directly to your machine from the ISP, then perhaps you
can eliminate the forwarding from list1 at ... and list2 at ... to the email
account mailmansrv at mydomain and have fetchmail pick up the mail
individually per list and deliver only to that list.

Your basic problem is that mailman is designed to run on the server that
receives the list mail directly. Because of whatever restrictions exist
that prevent that, you (or someone) have come up with this fetchmail
kludge and it doesn't work because of the duplication.

Others have made this work by having separate mailboxes on the host for
each list, list-owner, list-subscribe, etc. address and using fetchmail
to deliver mailbox by mailbox to the appropriate place on the Mailman

Mark Sapiro <mark at msapiro.net>        The highway is for gamblers,
San Francisco Bay Area, California    better use your sense - B. Dylan

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