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Re: Every spam is sacred

On Sat, Jun 14, 2003 at 02:02:38AM +0200, Santiago Vila wrote:
> Assuming that we receive approximately the same amount of spam and non-spam
> (a recent survey says that spam is now more than 50% of all email),
> the Bayes rule says that probability that a message sent from an IP in
> the DSBL is spam is about 99.95%. This is equivalent to saying that
> for each approximately 2000 messages that you receive from an IP
> listed in the DSBL, only one of them is not spam.

That doesn't seem right. The only figures I can find are around 30% and my
personal experience tells me it's less, but I guess it varies
person-to-person. Secondly, you're placing too much faith in DSBLs being
accurate. If they added the whole of australia to their blacklist, your
false-positives will be much, much higher. Someone else on this list had
some actual figures on how effective these blacklists are, it would only
knock maybe 30% off, hardly remove the problem.

Note, some open relays may also be used by legit customers, you're just
tossing them away without further consideration. Finally, while one in 2000
might be good enough for you, but if that one email happens to be very
important, you're screwed. Some people aren't going to take that risk.

> In other words: For you, Manoj, not to miss your valuable "false positive"
> I (and everybody) have to receive and handle 1999 spam messages.
> I think this is simply not fair...

How about you implement filter on your own machine; best of both worlds.

> Assuming some consensus in that if we were to choose a single DNSBL to
> be implemented site-wide-with-exceptions-for-those-who-ask, the DSBL
> would be a good choice, what would you think about making a list of
> people to be put in recipients_reject_except and asking debian-admin
> to enable list.dsbl.org for everybody except those who ask to be
> excepted?

Can it be opt-in rather than opt-out?

Martijn van Oosterhout   <kleptog@svana.org>   http://svana.org/kleptog/
> "the West won the world not by the superiority of its ideas or values or
> religion but rather by its superiority in applying organized violence.
> Westerners often forget this fact, non-Westerners never do."
>   - Samuel P. Huntington

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