Re: [Exim] TARPIT ACL - for Spam Control

6 May 2003, Giuliano Gavazzi wrote:

GG> I personally find tarpitting/teergrubing not an incredibly effective idea.
GG> If machine resources (and partly network bandwidth) are unlimited,
GG> you will receive exactly the same amount of spam, as soon as the
GG> system reaches equilibrium again.

What about exponential backoff algotithm? Each new message from same
host is delayed to increasing time. Administrator will have a time to
check logs and take measures against spammer (block the host, for
example), or release all these messages if they are legitimate.

Delay can also be accomplished by returning 4xx code to sending host, or
by leaving messages in queue for specified time.

BTW, many spam runs aren't coming from MTAs. So, if spam message is
temporary rejected, there are chances that it will not appear again in
future.

--
Alexey Y. Promokhov, system administrator
Joint Stock Venture "GP Telecom", Moscow, Russia