[Dovecot] Attachment extraction, de-duplication (was: Re: Scalability plans: Abstract out filesystem and make it someone else's problem)

[Steffen Kaiser]

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On Fri, 14 Aug 2009, Patrick Nagel wrote:

> able to see all attachments of all other mail receivers. So this only works in
> a cooperative environment.

One can extend that scheme a bit.

> In short, a script (implemented as filter, getting called by postfix) 
> extracts all attachments on arrival, using ripmime [1]. The attachments

We use MIMEDefang on the recieving MTA.

There I remove certain MIME parts and put them on a Webspace, the filename 
(aka URL) is the seeded SHA1 of the content. So it is not easy to guess an 
URL without already knowing the seed and the content or the mail itself.

However, the reactions to this action is quite wide spread. Some are glad, 
because they can download attachments on demand, others hate this extra 
step. Some user think the mail is altered and the copyright of the sender 
is infringed. In a few cases, I ripped some pictures from a HTML mail, 
which caused uproar. Also, the S/Mime and PGP signing won't work, if 
transmitted in a separate MIME part.

Bye,

- -- 
Steffen Kaiser
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