Re: [exim] Should queue processing be rewritten in Exim?

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著者: Dave Lugo
日付:  
To: exim-users
題目: Re: [exim] Should queue processing be rewritten in Exim?
On Wed, 2 Jul 2008, John Jetmore wrote:
>
>
> Postini claims their mail filtering works this way. They have X scanning
> subsystems (at least one spam and one virus, but my understanding is
> multiples of each). When a chunk of data comes in off the wire they feed
> that chunk into each of the subsystems. Those subsystems may or may nor
> choose to analyze that chunk of data or wait until it has more data. When
> it has enough data to make a decision it can return a verdict at any point
> in the exchange, even if it hasn't seen the entire message (for instance,
> once it has enough data to see a mime boundary, that or the next chunk
> containing the start of the file might be enough to see a virus
> signature). I'm not sure if one positive subsystem is enough to flag the
> entire message, but once enough subsystems have marked it as bad, the MTA
> can start binning the incoming data stream until the dot is sent and they
> can tell the sender it's rejected.
>


This sounds about right ($dayjob is a postini reseller)


> Obviously Postini is highly motivated to do this well and efficiently and


I would hope so - but I've also seen situations where they are way behind
the curve on.


> I'm not suggesting Exim should be able to do this, just pointing out that
> it can and has been done. Of course, Postini has written all of their own
> subsystems too, they don't just plug into a out of the box clamav or
> spamassassin...
>


Yup. It's all proprietary, as far as I know.


-- 
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Dave Lugo   dlugo@???    LC Unit #260   TINLC
Have you hugged your firewall today?   No spam, thanks.
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