mapSoN is an anti-spam system that uses an approach which is entirely different than other systems. Instead of trying to recognize spam by the IP address of the SMTP dialog's peer or by certain patters in the mail's body, it uses the sender's email address to decide whether the e-mail is delivered to your mailbox or not: Any email that comes from a "known" address may pass, but any email that comes from an email address seen for the first time needs special confirmation before it may pass. "Special confirmation" means that mapSoN will generate an MD5 checksum of the to-be-confirmed email and store the email in a temporary spool directory. Then it sends a request for confirmation to the address from which the mail was coming. In this request, it will include the MD5 checksum and ask the recipient to reply back and to quote that MD5 hash. Once it sees that MD5 hash again, it considers that a confirmation of the original email, delivers the deferred email from the spool to your mailbox, and adds the sender's address to the database of known addresses, so that the next time he tries to contact you, his mail will pass through immediately. This heuristic catches almost any spam email, because spammers have to fake their sender addresses in order to avoid being held responsible for their abuse. Hence, their address will most likely not be in the database of known addresses, nor will they ever receive the request for confirmation email.
|Tags||Communications Email Filters|
|Operating Systems||POSIX Unix|
Release Notes: Minor documentation clean-up.