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Re: What would happen to Challenge/Response if ...



On Thu, Oct 23, 2003 at 09:20:46AM +0100, Karsten M. Self said
> on Thu, Oct 23, 2003 at 05:32:59PM +1000, Rob Weir (rweir@ertius.org) wrote:
> > If you have the level of MTA control neccessary to automatically reply
> > to CR queries, then just block Swen at the MTA level.  I've rejected
> > 34552 incoming Swen mails in the past few days, before my MTA even
> > receives them.  Unfortunately, my secondary MXs don't know to drop that
> > crap, so they accept it and then try to send it on to my mail server,
> > making that count rather inflated.
> 
> Incidentally, a friend tells an anectdote of turning on teergrubing in
> exim4 per Marc Merlin's configuration...and promptly teergrubing the
> hell out of his secondary MXs.  Might want to ensure that these are
> excluded from any countermeasures you take.

Good point.  SA has been working so well lately that I haven't
bothered to implement any teergrubing at all yet, but I'll bear that in
mind.

> > Imagine that instead of dropping that shit on the floor, you sent a CR
> > query.  You've just doubled the number of mails flying around (thought
> > not the volume, of course).
> 
> Doubled mail.  For no useful effect.  And required 4GB of spool space,
> extended over the 1-2 weeks you hold your contested mail.

Yup.  Reason #23131 why CR is a poor solution.  I'm quite amazed at how
well SA and simple checks like my Postfix body regexp work.  I still get
spam, and oodles of it, but it's almost flawlessly classified.  I check
out my spam folders every few days, and I've found perhaps five false
positive in the past...3 months, more?  False negatives are a smallish
issue, but almost everything that gets through is either too small for
bayesian to work effectively, or CJK spam that I can't even read.

-- 
Rob Weir <rweir@ertius.org> | mlspam@ertius.org  |  Do I look like I want a CC?
Words of the day: USCODE Iran quarter North Korea Cheney North Korea quiche MD2

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