Abstract: One aspect of the present invention provides an Email Firewall system and/or method, which is a system for selective delivery of electronic mail (email), within the framework of conventional email protocols, and authentication of the source of electronic mail, with an objective of blocking unwanted email. In one embodiment of the present invention, the system resembles a firewall in the sense that the Email Firewall checks if the sender has “clearance” before forwarding the email message to the recipient and a means for providing “clearance”.