greyd is a transparent Greylist proxy for the purpose of rejecting spam send by spambot armies. The first generation of code which has been running in production for about 3 months has greatly reduced the amount of spam that needs to be processed by conventional anti-spam techniques.


Before this project was taken on a moderate amount of research was conducted to find an existing package that could meet the needs of proxying mail for unconventional SMTP servers (such as zmailer). Principally two packages were identified.

One was based on an old library that has not been maintained for 6 years, generally hard to find and would not compile under current Linux OSes without a lot of work. The other required many dependent packages which was beyond the scope of implementing a simple solution.

greyd is written entirely in Python and only requires that the Twisted framework be installed. Since Twisted is a pure Python framework it is virtually impossible to have installation problems if a valid installation of Python is available. This project is a simple design that can be used nearly on any OS (in theory even Windows platforms or with very little porting efforts) and will work with any SMTP server without having to modify the SMTP configurations as most Greylist solutions do.