• 
  

Barracuda Technology

The Barracuda Spam Firewall provides comprehensive spam-blocking for your organization. The algorithms and methods used by the Barracuda Spam Firewall are the most comprehensive and most advanced in the industry. The Barracuda Spam Firewall even includes Bayesian analysis which has been shown to be the most effective and most accurate method of blocking spam.

The methods and techniques used by the Barracuda Spam Firewall are continuously updated via the hourly Barracuda Energize Update Service, to stay one step ahead of spammers and virus writers.

The Barracuda Spam Firewall provides a number of parameters that can be adjusted and tuned for your specific environment.

Some of the algorithms employed to block spam are listed below with a short description.

Technique	Description
Blacklisting of Web sites & domains	Barracuda Central maintains an up-to-date list of the largest and most aggressive known spammers. This list is maintained by both Barracuda Networks and other anti-spam groups. This list is automatically updated on each Barracuda Spam Firewall.
Keyword scanning of emails	This can be configured on a per-user basis. Our scanning methods include a scoring system such that emails are scored based on a number of criteria. If the score is above a threshold, then that email is flagged as spam. The Barracuda Spam Firewall comes with default thresholds that can be changed according to user preferences.
Checksum technology	Barracuda Central monitors email traffic via the Internet and uses checksum technology to keep track of the number of times a particular message has appeared on the Internet. If a message has appeared very broadly, it would be categorized as "known spam". Checksums of known spam messages are utilized by the Barracuda Spam Firewall to block spam messages.
Message authenticity checking	Several algorithms are utilized to verify the authenticity of a message. Some of these are simple checks to verify that the from address is authentic. Some are more complex relating to SMTP protocol.
Blacklists & Whitelists	Domains, IPs, and email addresses can be blocked or whitelisted (allowed through). These lists may be maintained on a per-user or corporate basis
Rate controls	Rate controls are utilized to stop DOS (denial of service) attacks as well as dictionary based spam attacks. Rate controls are are integrated and automatic in the Barracuda Spam Firewall.
Bayesian Algorithms	Bayesian filters are personalized to each user and adapt automatically to changes in spam trends and definitions. To determine the likelihood that an email is spam, these filters use Bayesian analysis to compare the words or phrases in the email in question to the frequency of the same words or phrases in the intended recipient's previous emails (both legitimate and spam).
Spam Fingerprint Checking	Fingerprinting techniques examine the characteristics, or fingerprint, of emails previously identified as spam and use this information to identify the same or similar email, each time one is intercepted. These real time fingerprint checks are continuously updated by Barracuda Central and provide a method of identifying spam with nearly zero false positives.
Intent Analysis	Intent Analysis is used to look at the objective or goal of the email. If the objective of the email is to sell something, (such as click a URL) , or get the user to take a particular action that is indicative spam, the email will be categorized as spam.