Re: [exim] Preventing TXT lookups after successful acl modif…

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Author: Mar Matthias Darin
Date:  
To: exim users
Subject: Re: [exim] Preventing TXT lookups after successful acl modifier dnslists processing
Hello,

Mike Cardwell writes:

> Doesn't using DynaStop involve calling an external executable using
> ${run} which reads several flat files and uses up IPC shared memory in
> order to obtain relatively stale results?
>
> In what regard does DynaStop provide any advantage over using a plain
> dnsbl? The guy is trying to reduce the time exim processes run, not
> increase them...


DynaStop does use shared memory for the cache that expires after 24 hours or
the oldest entry remove in the case of it being full. The "flat files" are
heavily maintained (some updated daily) The results are hardly stale as any
"new" IP addresses are looked up in realtime. New being defined as not in
its cache.

The advantages are thus:

DynaStop is light and faster then spamassassin, see
http://tom.knaupp.com/?p=9

Reduced load to spamassassin means the availability of tools like fuzzyocr
can be deployed. DynaStop can also be used to aid in the training and
accuracy of spamassassin (or dspam).

DynaStop catches more IP addresses then the RBLs. See the following:

http://tanaya.net/DynaStop/IPComparitive.html

http://www.exim-users.org/forums/showthread.php?t=54012

Of the 373,302,000 IP addresses tested (Aug 1/07) 85% (317,306,720) where
evaluated to be dynamic. The estimated 10% ligitimate mail servers that use
dynamic IP addresses (based upon user feedback) can easily be excluded
leaving 279,976,512 IP addresses (potential spam zombies) that will be
blocked/tagged by DynaStop.


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DynaStop: Stopping spam one dynamic IP address at a time.
http://tanaya.net/DynaStop/