Re: [sieve] [apps-discuss] I-D Action: draft-ietf-appsawg-sieve-duplicate-00.txt

Stephan Bosch <> Wed, 22 May 2013 22:19 UTC

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From: Stephan Bosch <>
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Subject: Re: [sieve] [apps-discuss] I-D Action: draft-ietf-appsawg-sieve-duplicate-00.txt
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This draft describes an extension to the Sieve mail filtering language 
(RFC 5228) called "duplicate". It adds the ability to detect duplicate 
message deliveries. The main application for this new extension is 
handling duplicate deliveries commonly caused by mailing list 
subscriptions or redirected mail addresses. Using this extension, the 
user can for example decide to move duplicate messages to a special 
folder, mark them as 'seen', or discard them altogether.

I first implemented this extension a little more than a year ago as a 
vendor-defined extension for my own Sieve implementation (Dovecot 
Pigeonhole). I did this upon repeated requests from users. They were 
looking for a Sieve-equivalent of what could be achieved with Procmail 
using `formail -D`. Since then, I extended it a bit and eventually I 
made it more generic. In January of this year I decided that it may be 
suitable for proper standardization, so I posted the specification on 
the Sieve mailing list 
There, it was first picked up and reviewed by Ned Freed and Alexey 
Melnikov and I turned it into a first I-D submission.

The next versions -01 and -02 were discussed in these threads:

At this point it was decided that the document was sufficiently mature 
to start the process of becoming a proposed standard. Since the Sieve WG 
is no longer the obvious place to do this, it was moved to APPSAWG. 
Apart from its name, the new submission 
draft-ietf-appsawg-sieve-duplicate-00 is identical to 

The following are known issues we haven't addressed in the latest 
version so far and I think these should be discussed a bit more:

- Do we measure the expiry time of entries in the duplicate tracking 
list relative to the initial message or relative to the last duplicate 
Should we make this configurable?

- Is the "duplicate" extension supposed to be active in IMAPSieve (RFC 
6785) context 
Currently, consensus is to mark this as NOT RECOMMENDED.

I'd like to finish this document some time in July or August. For that, 
it would be nice to get it thoroughly reviewed, so your reviews and 
comments are very welcome!


Stephan Bosch.

On 5/22/2013 10:39 PM, wrote:
> A New Internet-Draft is available from the on-line Internet-Drafts directories.
>   This draft is a work item of the Applications Area Working Group Working Group of the IETF.
> 	Title           : Sieve Email Filtering: Detecting Duplicate Deliveries
> 	Author(s)       : Stephan Bosch
> 	Filename        : draft-ietf-appsawg-sieve-duplicate-00.txt
> 	Pages           : 10
> 	Date            : 2013-05-22
> Abstract:
>     This document defines a new test command "duplicate" for the "Sieve"
>     email filtering language.  This test adds the ability to detect
>     duplicate message deliveries.  The main application for this new test
>     is handling duplicate deliveries commonly caused by mailing list
>     subscriptions or redirected mail addresses.  The detection is
>     normally performed by matching the message ID to an internal list of
>     message IDs from previously delivered messages.  For more complex
>     applications, the "duplicate" test can also use the content of a
>     specific header or other parts of the message.
> The IETF datatracker status page for this draft is:
> There's also a htmlized version available at:
> Internet-Drafts are also available by anonymous FTP at:
> _______________________________________________
> apps-discuss mailing list