Re:Filtering email (Score 0)

That tool already exists. It let's you pre authorize people that are allowed to send you mail, and those that you want to drop on the floor. It will even queue a message and send a confirmation message to the author of a message that you did not pre authorize. If they respond, just by sending an empty reply. It can add them to your filter list and allow the message through.

Check it out. tmda.sourceforge.net