Mail filtering ideas

The standard configuration includes Spamassassin because, in my experience, it works great: it correctly flagged about 99% of the spam I received over a period of a month, and there was only one false positive, which was an automated response from Hotmail... to a spam report I'd sent them.

Over at buffy.riseup.net, they're using Bogofilter, which is Eric Raymond's implementation of Bayesian filtering. I don't think it could be used for mailing lists, though, since it requires users to sort their mail into spam and ham. The idea is that each user has their own definition of what spam is for them. But a mailing list server needs to be able to identify spam in general.

On the lists I've maintained recently, there have been tons of messages containing virus-carrying attachments, which I have to manually delete as moderator. This is a huge pain, so I'm keen to use whatever will filter out those viruses. The only decent free virus checker seems to be Clam AntiVirus -- it has a pretty good virus database, and it's lightning fast -- so that's what's in the standard configuration. However, its virus database doesn't get updated as quickly as the commercial ones, so some viruses are likely to get through.

I'd like to try adding Anomy (which the buffy.riseup.net sysadmins mention but aren't using yet); it just looks for things like Visual Basic attachments and dodgy JavaScript, rather than particular viruses. It seems like a good idea to me. This article explains how to set it up in conjunction with Postfix and Spamassassin.

-- BenjaminGeer - 02 May 2003
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