Spam Filter

Atqui is an add-on service for existing e-mail accounts. In fact it is a third party service with a nice web interface. If your inbox receives an e-mail from unknown senders, the sender receives a polite message asking for "verification". This is only done once, and only takes a few moments to complete. See atqui.com for details.

AppRiver is a filtering solution for Novell GroupWise and MS Exchange.
It provides one of the easiest to implement spam filtering and virus protection solutions for Exchange, GroupWise and Domino.
It has a web interface for managing domain configurations and quarantine areas plus four safety checks to make no false positives. Scalable to hundreds of thousands of users. See appriver.com

Activator Mail is a virus scanning and spam prevention software based on blacklists and feedback from users. ActivatorMail consults 30 major spam blacklist databases and milions of keywords and heuristic filters to carefully qualify or weight each e-mail message.

Sam Spade is an integrated network query tool for Windows XP. It can also be effectively used for tracking down spam. SamSpade runs on a dedicated server collocated at Los Nettos using bandwidth donated by CenterGate. A second -backup- server is hosted by MAPS. Most services are provided via web interface.

MicroSieve is a freeware USENET spam filter. It has been tested on GNU/Linux and Sun Solaris platforms along with Cyclone and Typhoon news servers. Microbrew MicroSieve was designed to be a high speed spam filter for USENET news. It is faster than other Perl-based filters. Similar to other Microbrew products, MicroSieve is released under the GNU General Public License.

MailWasher is an easy way of managing your e-mails before downloading to the computer. The program is free of charge. Extra options are available if you want to upgrade - free to try. Mailwasher is easy to setup and use even for unexperienced users. Downloads at mailwasher.net

K9 works with your regular POP3 e-mail program. It automatically classifies incoming e-mail as spam without any need of maintaining multiple rules or regular updates. It uses an intelligent statistical analysis with high precision. K9 is able to learn, and improves all along by processing more and more messages. K9 is designated for standard POP3 e-mail accounts only.

SpamBrave is a Bayesian-type spam filtering plug-in module for Microsoft Outlook Express. It makes a use of an intelligent Bayesian algorithm to filter out spam. SpamBrave analyses e-mails using a number of parameters and memorizes statistical data. After a couple of training days it should filter out more than 90% of unwanted e-mail messages.

There are many commercial anti-spam solutions which are suited for small businesses to enterprises. Katharion (www.katharion.com) comes with an easy to setup solution compatible with major e-mail server systems taking low maintenance efforts. Katharion offers free e-mail and phone support. The software seems to be very easy to integrate and use. For the low price it offers a great service.

Having been created as an open-source project at the Apache Foundation, SpamAssassin seems to be one of the best spam filters available. It can be installed and configured very easily, with almost no additional fine tuning. Once installed on the mail server, the amount of incoming spam messages decreases significantly. The software can be used with many different e-mail server systems.