Subject: Re: New Paul Graham Article
From: Erik Naggum <>
Date: 17 Aug 2002 03:51:05 +0000
Newsgroups: comp.lang.lisp
Message-ID: <>

* (sv0f)
| On a statistical approach to filtering spam, with Lisp code, here:

  Spam has to be dealt with at the transport level.  The ability of strangers
  to send you mail must be curtailed.  Several large sites offer a system to
  reject all mail from unknown correspondents, temporarily or permanently, and
  wait for the reader of the log to accept incoming mail from addresses that
  look familiar.  Another option is to accept delivery but return transport-
  like error messages if the user does not want the message.  Yet another
  option is to see if the smtp client is set up to accept mail for the domain
  that it tries to deliver mail from.  Yet another option is to temporarily
  reject all mail from unknown sources and utilize the fact that spammers have
  no resources to queue messages for later delivery.  And then you can always
  implement a scheme that returns a temporary rejection, but sends a mail to
  the originator independently asking for confirmation that he is human and by
  accepting the conditions that unsolicited commercial e-mail carries a fee
  that /will/ be collected.  Failure to accept the conditions will cause the
  temporary rejection never to be lifted, thus using up queue space in the
  offending server, which any sysadmin will notice and take care of even if
  they do not bother to fix their system configuration to avoid relaying spam.
  Should the conditions be accepted, the message is allowed through.

  If you allow the message to be delivered and waste CPU or brain time, the
  spammers have won a small victory.  That is just wrong.  Spammers must die.

Erik Naggum, Oslo, Norway

Act from reason, and failure makes you rethink and study harder.
Act from faith, and failure makes you blame someone and push harder.