Re: [Exim] SPAM control

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Author: Dennis Davis
Date:  
To: exim-users
Subject: Re: [Exim] SPAM control
>From: Matthew Palmer <mjp16@???>
>To: exim-users@???
>Subject: Re: [Exim] SPAM control
>In-Reply-To: <63512816671.20030715084853@???>
>Date: Tue, 15 Jul 2003 20:24:28 +1000 (EST)
>
>On Tue, 15 Jul 2003, Alexander Prohorenko wrote:
>
>> I'd like to install some resource-friendly SPAM control software
>> for Exim, like SpamAssassin is. Unfortunetly, my mail server is
>> running pretty old hardware, so SpamAssassin easily kills it with
>> a load. Perl doesn't work good for us, though Mailman's Python
>> works fine. I've tried a lot of tuning option for SpamAssassin,
>> but still it needs too much resources. However, I'd like to
>> install some SPAM control, because a lot of SPAM really abuses
>> our customers.
>
>Content filtering requires a certain level of processing power to
>happen - take the input, run your matching over it, and then do
>something appropriate with the result. There's no way you're going
>to get that beyond a certain level of processor grunt.
>
>If you're willing to go a different path, you can save processing
>(and bandwidth, to boot) by using DNS blocklists. Good ones have
>very minimal false-positive rates (and bounced senders can always
>make other arrangements for information delivery).


I'll endorse that. See:

http://www.declude.com/JunkMail/Support/ip4r.htm

for a comprehensive list. Take your choice on what's best for you.
Opinions will vary, but:

http://www.spamhaus.org/

seem reliable and conservative along with:

http://www.mail-abuse.org/

Also have a look at Easynet's list of suspect envelope senders:

http://abuse.easynet.nl/spamlist-usage.html

I'm using this list here, and it is a cheap way of rejecting email.
As usual, your mileage may vary.

>But honestly, if you're being paid to provide this service, you
>*should* be able to afford reasonable hardware to run on. I've run
>SA+amavis+exim on a P166 for a smallish organisation (15 people).
>The machine ran reasonably well, with some load management options
>in exim (to not run delivery processes when the system load got
>up).


In general running SpamAssassin is more expensive than virus
checking. If you do use it, consider limiting the size of message
you scan. I only run SpamAssassin on incoming messages of 64K or
less. Others will use 90K or 128K. But may sure you do use a
limit.

>At <AU$700 for a basic duron system which would fly for mail
>processing, any commercial service should be able to find the money
>to buy at least a machine like that.


Quite, hardware is now relatively cheap compared to the people whose
time it will save.