Re: [vps-mail] filtering non local account with spamassassin and clamav

[Scott Wiersdorf <scott@xxxxxxxxxxxx>]

On Wed, Dec 10, 2003 at 07:22:21AM +0100, ADNET Ghislain wrote:
> Thanks  Scott,
> 
>   i was wondering if there was not a way to tell sendmail : just go
> throught filter 1 then filter2 (spamassassin/clamav) instead of using
> external shell or procmail recipe. I am starting to read about the
> milter lib for sendmail. 
> 
>   If there is no other way i will use procmail or a shell script but i
> really find this not really the best solution to launch a third program
> just to pass the mail to a filter :). I have done no testing about
> performance of the procmail thing but if sendmail can do the job this is
> an economy of processing power, and if i got a lot of emails then it can
> save the day. 

The bottleneck is not in forking a subshell--that operation is fairly
fast. The 90% of your time will be spent in actual spam/virus
scanning, since both of these are expensive operations. I haven't any
benchmarks, but clamav is actually quite fast. It does a checksum on
any attachments and does a fast hash lookup which doesn't take long at
all.

With a milter, you reduce the 10% fork cost to maybe 5% since you
still have to open some sockets and pass data, but the 90% of your
time is still spent scanning (again, these numbers are not intended
to be precise, but in general the bulk of the overhead is not in the
fork).

Scott
-- 
Scott Wiersdorf
scott@xxxxxxxxxxxx
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