Re: avoiding duplicate messages with multiple lists

hi,

On Thu, 2006-10-05 at 12:39 +0200, Werner Reisberger wrote:
> Quoting Jamie Zawinski <[email protected]>:
>
> SmartList can do nothing here without heavy modifications. It's rather  
> a question of duplicate delivery suppression on the recipient or MTA  
> site. E. g.
> the cyrus imap/pop3 server would deliver only one copy (with the default
> configuration). Probably there is also a solution at the MTA (postfix) side.
> You should ask the postfix community.

at http://www.postfix.org/faq.html#duplicate you can read how Postfix
behaves,

Postfix sends duplicate mail
Some people will complain that Postfix sends duplicate messages. This
happens whenever one message is mailed to multiple addresses that reach
the same user. Examples of such scenarios are: 

      * One message is sent to the user, and to an alias that lists the
        user. The user receives one copy of the mail directly, and one
        copy via the alias. 
        
      * One message is sent to multiple aliases that list the user. The
        user receives one copy of the mail via each alias.

Some people will even argue that this is the "right" behavior. It is
probably more a matter of expectation and of what one is used to.

This can be "fixed" only by making Postfix slower. In the above
examples, Postfix would first have to completely expand all distribution
lists before starting any delivery. By design, Postfix delivers mail to
different destinations in parallel, and local delivery is no exception.
This is why Postfix can be faster than sendmail.

So, there's no fix on the Postfix side either.

Miquel

-- 
Miquel Cabanas, TSSR -----------------------------------------------
Servei de Ressonancia Magnetica Nuclear,
Universitat Autonoma de Barcelona 
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