From LogSat Software:
SpamFilter is used by ISPs and companies running their SMTP servers. It is designed to be a proxy to your incoming SMTP server receiving all e-mails addressed to your domain. If the sender's IP is not blacklisted in DNS-MAPS based black lists then the e-mail is forwarded to your SMTP server. Our new SFBD (SpamFilter Distributed Database) is a huge database of spammer's IPs updated in realtime by all SpamFilter installations in the world. Anytime a company running SpamFilter ISP blocks an email, the sender's IP address is sent to our centralized SFDB database. This allows the SFDB filter to have access to a huge repository of spammer's IPs, updated in real-time by all the SpamFilter ISP installations in the world. Our database analyzes this data in realtime, and will block IPs that have sent excessive amounts of spam to multiple locations in the world in the spam of the previous few minutes. This allows the SFDB to be extremely accurate, effective, and to start blacklisting IPs within minutes of them sending spam. Our propietary SFDC (SpamFilter Distributed Content) filter is the latest filtering technology developed by LogSat Software. When SpamFilter ISP receives an email, it will analyze the email's contents and will calculate a 20-byte hash to characterize it. We developed technology that is able to detect similar emails based on their contents. SpamFilter will assign the same hash to similar emails. When SpamFilter detects that emails with the same hash signature are originating from several different locations, it will report such anomaly to our centralized servers. Our database analyzes, in real-time, this incoming flow of messages, and, based on their quantity, origin and destinations, is able to detect what signature hashes are generated by spam emails. The technology behind the SFDC allows our centralized database to detect spam signatures regardless of the email's text and contents, but rather base it on the patterns used by spammers to deliver their emails. A new filter to scan inside embedded images is also included. Statistical Bayesian DNA fingerprinting, along with dozens of blacklist/white rules are also be applied to filter spam. Examples are country filters, SPF and SURBL filters, remote DNS validation tests. An optional antivirus plug-in is available. End users have Web access to their quarantined e-mails. They can view, delete, and force delivery of their own quarantined e-mail without having to ask the system administrators.
What's new in this version:
Version 4.6 features several more filtering techniques and support for 64-bit.