Patent attributes
A system for eliminating unauthorized email sent to a user on a network analyzes the sender address of incoming email and determines whether it is to be rejected by returning a standard “no such user” error code or accepted depending upon executing processing rules and analyzing managed lists of authorized senders. This provides an advantage over existing anti-spam filtering systems by intercepting unauthorized email before it reaches an existing email server or client. The system rejects all email unless authorized by using a standard “no such user” error code, and by redirecting the unauthorized email back to the sender or to a sender evaluation site. An ASL module captures authorized sender addresses from the user's outgoing email and other sources in order to update “authorized senders” lists. The system may employ a WBM procedure that notifies senders of rejected email to go to a separate website and register as valid senders after passing an interaction test that precludes automatic registration by a mechanical program. A destination proxy email address procedure allows subscribers to use temporary proxy addresses for receiving email expected from unknown sources and instantiates senders as authorized upon receiving the expected email to the proxy addresses. The unauthorized-email rejection component can be readily configured as a hardware or software appliance used in tandem with a conventional email server, email gateway, or firewall to an intranet, or as a software extension to an existing firewall system.