On Tue, 2 Dec 2003, Justin Gombos wrote:
JG> * Ruud H.G. van Tol <rvtol(_at_)isolution(_dot_)nl> [2003-12-02 14:31]:
JG> > As a proof-of-concept, I am developing a greylist-model
JG> > with procmail. Here I present the first step, which is
JG> > not very practical but you might want to learn from it.
JG>
JG> What's the idea behing greylisting? It looked to me like that script
JG> would trash new messages, and retain the dupes. How is that useful?
JG>
The concept is based on the premise that a normail mail server, on receipt
of a temporary failure, will try again whereas a spam generator has no
such sophistication and is a "send and forget" program. So if you fail,
temporarily, every message the first time you see it, and accept each
message the second time you see it, the process will cut out a lot of
spam.
My ISP uses it for the mailboxes it hosts and I understand it is very
effective. One person in the local newsgroup reported that some webmail
clients seemed to be "send and forget" so it is not without problems if
implemented at a commercial level.
As I run my own mailserver, a procmail solution that instructed sendmail
to issue a temporary failure sounds interesting.
--
Alan
( Please do not email me AS WELL as replying to the list. Please
address personal email to alan+1@ as lists@ is not read. A
password autoresponder may be invoked if this email is very old. )
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