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Re: Which spam filter do you use?



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On Friday, October  5 at 01:22 PM, quoth Eyolf Østrem:
> So this does in fact mean that without that extra time tending the 
> rules, SA may actually let more spam through? 

As in most cases, the answer is "it depends". It *may* let more spam 
through. In my case, I use SA for everything, and I train it on 
everything I can lay hands on---and have for years. I didn't notice a 
difference in performance (for my personal mail) when I added 
sa-update to the crontab. On the other hand, not everyone on my server 
uses the training folders, and so their spamassassin configurations 
don't adapt as quickly to new spam trends. That is where, on my 
system, updating the rules files really helps with.

But everyone has different experiences.

I will say, though, it is true that SpamAssassin is really slow, but 
not for the reason many people claim. We have a pretty standard 
spamc/spamd setup, and if I turn off all the network tests, it flies. 
But, because I find the extra tests SA performs valuable, I have it 
crunch through all the various DNS, DKIM, and remote-spam-database 
tests, which adds significantly to its average processing time. 
According to my logs, it takes anywhere from 4 to 16 seconds to 
process each message, which is pretty hefty! Then again, it's 
processing mail at delivery time so most folks don't notice, and it's 
doing it all in parallel... but because of those network tests, it's 
unlikely that I could improve performance significantly by putting it 
on a faster machine. If my email server was under heavier load, I'd 
probably have to look into changing my filtering setup (put SA on a 
different machine, boost my dns cache size, maybe add a prefilter of 
some kind, etc.).

As for impact, it chunks through on the order of 5000 emails a day, of 
which over 86% is spam (according to my logs), and I think the last 
time I got a message that was incorrectly classified was probably... 
maybe a week ago, or so.

Some of my users have better experiences, some worse. Usually, if one  
of my users complains that they're getting too much spam, it's because 
they haven't been using the training features.

I think the real question you need to ask is: does my current spam 
system work sufficiently well for my taste, and what am I willing to 
pay to get better accuracy?

~Kyle
- -- 
To believe in God is impossible---to not believe in him is absurd.
                                                            -- Voltaire
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