[Ilugc] Spam Filters -SQLgrey
- From: linux@xxxxxxxxxxxxxxxx (Suresh Ramasubramanian)
- Date: Wed Aug 23 20:09:23 2006
~adarsh~ <vpadarsh@xxxxxxxxx> wrote:
Hi all,
Do anybody has hands on experience in using SQLgrey as spam filter.
How effective is this in filtering the mails.Also please comment on
DSPAM.
Graylisting is well .. kind of effective. But it has some interesting side
effects (that translate to massively delayed email) when it comes up against
another popular spam filtering method called "callbacks" where the receiving
mailserver connects back to the mailserver for the sending address, tries to
send a test mail to verify if the addess exists, before accepting mail.
[that callback thing is one of the defaults on cpanel and i think also plesk -
popular webhosting control panels .. and also used by some large isps like
verizon]
But aside from that, both graylists and "banner delays" are remarkably useful,
and "cheap" methods to cut down spam.
DSPAM, like Spamassassin, is a fairly cpu / disk etc heavy software that
assigns weighted scores to various spam characteristics. Normally - for regular
mailservers where you usually have far more capacity on the server, than you
have users, it should work just fine (you just have to keep tuning it to your
needs, and regularly updating it - its not a hero honda style "fill it, shut
it, forget it" thing).
For busy mailservers / very large installations you need to do something
different - concentrate on cheaper to implement solutions (well chosen smtp
blocklists, helo checks, banner delays etc)
Long story, that .. and it is not possible to give you a specific answer
without knowing a lot more details - and without your asking specific questions
(more specific than "how effective is technique X and software Y")
srs
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