GLD-fork is a fork of the GLD program written by Salim Gasmi. The fork has been made because the original project has been dead for many years now and some new featured were needed.
GLD-fork, as the original GLD, adds greylisting functionality to the postfix mailserver. Greylisting is a fairly resource friendly anti-spam technique. GLD-fork can easily be combined with other (more resource consuming) tools building the best anti-spam experience you can want on your system.