[OT] Spam filtering (was Re: [Imap-uw] Outlook deadlock)

[Andy Lyttle]

> FWIW I am religiously opposed to content-based filtering for exactly
> this reason.
>
> I "filter" only with blacklisting and greylisting. Although they  
> can only
> be done at a boundary mail exchanger, I find it invaluable that  
> there's
> really no such thing as a false positive; if legitimate mail  
> bounces then
> it, well... bounces.

I do all kinds of crazy filtering.  Some is content-based, although  
recently I've been focusing on other criteria.  Yes, there have been  
occasional false-positives; when I find one, I fix it so it doesn't  
happen again.

I do content-based filtering only after all other filtering options  
have been exhausted.  Messages with a sufficiently high score, I  
don't bother looking at, and false positives there are nearly zero.   
Messages with a questionable score, I do check periodically, so any  
legitimate messages aren't lost, I simply don't see them as quickly  
as I would if they weren't filtered.  I find this situation much less  
annoying than if I were to turn off content-based filtering altogether.

One thing I haven't set up yet is greylisting.  It sounds very  
effective, but I have some users that depend on being able to receive  
an e-mail immediately (e.g. while they're on the phone with the  
sender), and get quite annoyed when there's a significant delay.  I  
know, that's not how e-mail is supposed to work, but who am I to tell  
them that?  Still, I do want to do greylisting in certain cases; I  
just haven't gotten around to setting it up yet.

Ugh, I hate spam.

~ Andy