• Spam Scoring:
  The rules- based system (about 4000 rules) that looks for characteristics in the email. The Spam scores are used to determine what to do with the email. They do not contribute directly to the future analysis. The rules are updated via the Energize Updates Subscription.
   
• Bayesian Analysis:
  Contributes to the Spam scoring. This is done using emails that you flag as either SPAM, or NOT SPAM in the message log.
   
• Email Fingerprinting:
  The identification of exact or substantially similar emails via the Barracuda Central clearing house. When an email is identified as being Spam, it is also sent to our clearing house and fingerprinted.

The Barracuda Spam Firewall uses each of these techniques to consistently block spam. For more details, see FAQ #4, under the heading CudaMail Service Questions: "4.  How is SPAM Filtered?"