[Mailman-Users] duplicate messages

[Ryan Stasel]

Adam, 

My bad, as I realized it wasn't an MTA, but was caught up reading something else when I was typing. However, this doesn't change the fact that previously, Cyrus did duplicate suppression, and Dovecot does not... which is why this worked when my imap/pop server was Cyrus, and now I get duplicates with Dovecot. 

I'm not sure postfix (the MTA) should be doing the duplicate suppression. But looking around online, it seems like there is a very large argument that goes something like: "Dovecot should do it" -> "It's not dovecot's problem, it's the maillist software" -> "MTA should do it" -> "Dovecot should do it". -> Rinse, Repeat. Oh, and some argue something like procmail/sieve should do it. 

Given all that, dovecot probably shouldn't do duplicate suppression. Needless, though, there's still seemingly no good answer for those that use Dovecot for imap/pop. 

BTW, this is the closest I can find: http://wiki.dovecot.org/MTA

-Ryan Stasel

On Jan 5, 2010, at 09:13 , Adam McGreggor wrote:

> On Tue, Jan 05, 2010 at 08:28:58AM -0800, Ryan Stasel wrote:
>> On Jan 5, 2010, at 06:59 , Mark Sapiro wrote:
>>> 2) something in the outgoing MTA to you path that used to deliver only
>>> 1 of multiple messages with duplicate message-ids changed and is no
>>> longer dropping dups.
>> 
>> This looks like the case. It looks like Dovecot doesn't have any
>> kind of duplicate suppression (at least, not that I can find
> 
> Dovecot is *not* an MTA. 
> 
> q.v. <http://wiki.dovecot.org/MailServerOverview>:
>    "As an IMAP and POP3 server, Dovecot provides a way for mail-user
>    agents [MUA] to access their mail. As such, Dovecot is NOT
>    responsible for receiving mail from other servers. Dovecot
>    presents mail already stored on the system to MUA's."
> 
> or, indeed,
>    <http://www.dovecot.org/list/dovecot/2009-November/044640.html>
> 
> (I thought the expression "Dovecot is not a[n] MTA" was *somewhere on
> the dovecot wiki, I can't seem to find it.)
> 
> de-duplication should be handled by the MTA before passing it to an
> IMAP/POP server
> 
> I'd go back to the MTA(s) (Exim, Postfix, Sendmail, &c) config, and see
> what's going on there.
> 
> -- 
> ``The reasonable man adapts himself to the world: the unreasonable one
>  persists in trying to adapt the world to himself. Therefore all progress
>  depends on the unreasonable man.'' (George Bernard Shaw)