The Message Sniffer Antispam Plugin for SpamAssassin significantly improves the performance of SpamAssassin installations by providing a range of advanced features that improve both accuracy and speed without additional tuning.

• Add or subtract weight to SpamAssassin scores based on scan result codes.
• Add or subtract weight to SpamAssassin scores based on realtime IP reputation statistics.
• Optionally short-circuit other SpamAssassin tests based on scan result codes.
• Inject Message Sniffer headers for later analysis and easy debugging.

You can download SNF4SA from the Downloads page.  Use the Installation Guide for further installation help.