The SFDE filter has been developed exclusively by LogSat Software. Similarly to the SFDB and the SFDC filters, this filter uses a very powerful resource to stop spam: The entire global SpamFilter ISP user community.
This latest filter is proving to be one of the most effective and accurate tools in stopping spam.
Anytime a company running SpamFilter ISP blocks a spam email, SpamFilter will parse its contents and scan it for any email addresses it contains in the body. These will usually be email addresses associated with the spammer or the website the spam emails directs users to. SpamFilter will then create a unique hash for each email address in that email and will upload that hash to our centralized SFDE database. This allows the SFDE filter to have access to a huge repository of real spammer's email addresses, updated in real-time by all the SpamFilter ISP installations in the world.
Our database analyzes this data in realtime, and will block emails that contain the same hashed email addresses being reported as spam at that time. This allows the SFDE to be extremely accurate, effective, and to start blacklisting spammer's email addresses within minutes of them sending spam.
Email addresses from the database are automatically aged and removed from the database within 6-24 hours if they stop sending spam and/or viruses.