From: Dan Hollis (no email)
Date: Mon Apr 05 2004 - 15:33:15 EDT
On 5 Apr 2004, Paul Vixie wrote:
> that's why greylisting has been so effective -- to combat it the
> spammers would have to add the one thing they cannot afford: "state."
> see http://www.rhyolite.com/dcc/ for how to get started.
why is 'state' so hard to afford? they already have a list of email
addresses to spam, and they already have compromised boxes -- those are
the big costs for spammers. another byte of state per email address is
cheap (or if you are clever, a single bit stored in the email address
itself, which doesnt cost you anything).
i see greylisting being effective only as long as it doesnt get widely
deployed. as soon as greylisting starts having any impact on spammers,
they'll start spooling -- and it is very cheap to do so. after all, just
about everything on compromised boxes costs them nothing. and compromised
are the source of 99.9999999% of all spam.
-Dan
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