Abstract: The abstract must be less than 150 words, or 200 words when no figure is to be published. Proximity detection algorithms are used to determine whether or not the render of the message is authentic, by verifying if the sending host (242) is within proximity of registered MX Hosts 182, WWW Hosts, and/or DNS servers forth alleged sending domain. Proximity detection, combined with Select Reverse DNS lookups (153), provides extremely effective and accurate e-mail source verification system (110,107). As this combination relies solely on the existing Internet Domain Name System for its identifying matrix, an affective anti-SPAM system/method is realized without making any changes to any installed e-mail systems. In addition to proximit detection, Automatic Open Relay Test Administration (AORTA) (124,132) is used to perform Open Relay (118) testing on all servers attempting to send a message.