Re: Dangers of discarding duplicated messages

[Gene Rackow <rackow () mcs anl gov>]

There are lots of other things that may need to be done to handle 
dealing with duplicated message-id's as well.  Note that the RFC's
mandate that the message-id is unique per message.

A number of IMAP packages use the message-id as a way of keeping
track of the message in the various folders.
Having messages with the message-id breaks the standards, may
cause problems in message handling, etc.

The problem is bigger than just the anti-spam packages out there.

> From the original message it was indicated that these many dups 
might be picked up by the AV/AS software on the server.  If it is,
the blocking of the message should happen before the message-id
gets entered into the users cache of delivered messages.  Therefore
the 1st non-spam message should still be able to get through to the
end user.

-_Gene


Maciej Soltysiak made the following keystrokes:
> Hello Adrian,
>
> Thursday, February 17, 2005, 7:57:01 PM, you wrote:
>
> > It seems to be required that programs that automatically discard
> > duplicate messages have to use a checksum over the body and part of the
> > header of the emails instead of relying on the message ID.
> Very interesting indeed Adrian.
> So to sum it all up just for now, the advisories are two.
> One for users, one for developers of MUAs.
>
> Users: Beware of the fact that automatic discarding of duplicated messages
>       may result in you not getting the original mail in case someone exploi
>  ts
>       the effect Adrian depicted.
>
> Developers: Consider using checksum of the email messages, not only the
>            Message-ID to distinguish between duplicated messages.
>
> Am I correct?
>            
> Fortunately I was never using this MUA feature - I just take care of the
> duppies manually, which is not a big chore for me I must say.
>
>
> -- 
> Best regards,
> Maciej Soltysiak