Just about everyone needs an email filter.  Whether you are a 5-man shop in a home or a 200-person business, everyone wants the same thing - spam and virus free email.

With the cost of Exchange going thru the roof ($4100 for 50 users on Exchange 2007 Standard), organizations then get hit with additional costs for spam and virus filtering (upwards of $600/year for 50 mailboxes with most online services).

The Free Spam Filter provides business with a zero cost solution to manage spam and filter incoming emails for viri and suspicious files.  Zero cost does not mean low quality - SpamAssassin continues to be one of the best filters on the market, and ClamAV generally rates as well as commercial products.

Features

• a full Centos Linux virtual machine - based on Enterprise Redhat Linux, the most stable enterprise linux system out there
• Centos Linux 5.3 will have security patch support until 2014
• most of the setup is done via a couple of different web-based GUI
• SpamAssassin anti-spam and ClamAV antivirus provides total protection for your internal email system
• online database lookups and user training keep your filter current without reoccurring costs
• User-Friendly web interface allows users to manage their own quarantine, as well as train the filter to keep current with individual preferences
• If your backend exchange server goes offline, the spam filter will store emails & forward them when you get exchange online again - the default setting is 5 days of spooling
• can be setup to relay mail for authenticated users - this means you can still setup Blackberry and iPhones for remote email access, even if you have only 1 IP address for your internet connection

Prerequisite

• a PC running Windows XP, 2003, Vista, or Server 2008, 2gb RAM, 20+ GB free hard drive space, dual-core processor recommended, 32-bit or 64-bit OS
• VMWare Server 2 Free Edition - I used VMWare because it runs on any host - so you can run the spamfilter from a Mac or PC
• supports Exchange 2000, 2003, 2007, 2010, and is an excellent replacement/substitute for the SMTP edge server role in your Exchange 2007 infrastructure. That means this appliance can reside in a DMZ and forward mail to your internal exchange server(s).
• Putty or your favorite SSH client
• WinSCP or your favorite ssh file transfer client
• a good text editor (such as Crimson Editor)
• to zip your database backups, Infozip and knowledge of batch files would be good
• any workstation that will do spamfilter administration needs the above, and a Java Virtual Machine as well