denysoft_greylist

Description

Plugin to implement the 'greylisting' algorithm proposed by Ed Harris in http://projects.puremagic.com/greylisting/. Greylisting is a form of denysoft filter, where unrecognised new connections are temporarily denied for some initial period, to foil spammers using fire-and-forget spamware, http_proxies, etc.

This module was written by Gavin Carr, and the current version is available (together with other modules written by Gavin) from http://www.openfusion.com.au/labs/qpsmtpd/.

The version on this page contains two improvements over the version it is based on:

Docs

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Problems

The following MTAs do not handle temporary failures correctly and hence cannot send mail reliably to an MTA which implements greylisting: