SQLgrey is a Postfix greylisting policy service with auto- whitelisting and an SQL database as storage backend.
The project is based on postgrey, refining auto-whitelisting and storing whitelists and connection attempts in a database. Its goal is reducing the amount of spam reaching user mailboxes.
Here are some key features of "SQLgrey":
┬· SQLgrey can withstand a database crash (grey-listing is automatically switched off)
┬· 3 grey-listing algorithms to choose from
┬· Support for file-based IP and FQDN whitelists
┬· Support for fetching up-to-date whitelists from a repository
┬· Can mail the admin when the database is unavailable
┬· Auto-whitelists now understand SRS (SPF-aware mail forwarding)
┬· IPv6 support
┬· OPTIN / OPTOUT support
┬· Fine log controls
┬· Activity reports
┬· Net::Server::Multiplex (at least 0.87 is recommended, stability issues have been reported with earlier versions),
┬· SQLite, MySQL or PostgreSQL (PostgreSQL is recommended).
What's New in 1.6.8 Stable Release:
┬· Crash on syslog death bugfix
┬· Database handling fix (deactivated InactiveDestroy unless needed)
┬· Reopen database connection on SIGUSR1
What's New in 1.7.6 Development Release:
┬· Database handling fix (deactivated InactiveDestroy unless needed, should help solve memory leaks).
┬· Reopen database connection on SIGUSR1.