Spam relies on volume. Slowlists thwrart that. If you
throttle spam you can kill it, because spam's only selling point is
high volume at high speed. The goal of slowlists is the complete
elimination of spam from irresponsible ISPs by reducing it to an
unprofitable level. It does not directly address spam orginating
from rogue users of otherwise good ISPs.
Slowlists restrict a sender's volume of email by delaying the
receiver's response according to the reputation of (the IP address
of) the sender. Senders in good grace move email without penalty;
unknown senders are slowed, to provide a window to verify their
volume; probable spammers are asked to retry later, to show their
pennance. This last delay can be calibrated to squelch even the
huge number of open proxies. No email is ever rejected: only the
patience of the sender is tried.
A sender's good reputation is shared with other good senders, to
create a society of legitimate email movers. To be effective, a
slowlists society should be large and communicate as if they
were a single receiver, to throttle volume to any part of
the society. Outsiders can still send mail -- slowly -- and over
time gain the legitimacy they deserve.
Slowlists also use delay to distinguish legitimate senders from
spammers. Legitimate senders will cope with the initial delay until
their reputation earns them faster handling. For a spammer who
rushes the delay provides time for their tarnished reputation to
spread.
There are many definitions of spam, but we stand by this one: a
volume of email sent in excess of the sender's good reputation.
Slowlists attack spam at this very definition: limit the volume
of email received from unknown senders or senders in disrepute.
© 2003 Bryan Costales and Perforce, Inc. All rights reserved.
|