What is Spam Assassin?

What is Spam Assassin?
Spam Assassin is an extremely versatile open-source spam filter technology developed by Apache; the makers of the #1 web server software on the internet with almost complete market share control in the Linux website hosting market. Aside from Apache's already high level of respect in the web community, Spam Assassin takes the organization's credentials to the next level - and has been voted by many as the #1 spam blocker on the market as well. This offering is unmatched by other available email filtering software and considering it has been developed by the minds of Apache, we recommend it to all of our clients.

How does Spam Assassin work?
Using Spam Assassin couldn't be easier. To turn Spam Assassin on, simply select 'Spam Assassin' from the cPanel control panel, and switch the service on. Then, you can either choose to configure your junk mail filtering using the Horde webmail interface, or continue managing your spam assassin settings through the cPanel hosting system. SpamAssassin can be set up to work in a vast number of ways, and is totally customizable specifically to each of your e-mail accounts. Spam filtering supplied by this utility will work with all web, POP3, and IMAP e-mail hosting protocols.

There are several ways that SpamAssassin makes up its mind about a message:

• The message headers can be checked for consistency and adherence to Internet standards (e.g., is the date formatted properly?).
• The headers and body can be checked for phrases or message elements commonly found in spam (e.g., “MAKE MONEY FAST” or instructions on how to be removed from future mailings)-in several languages.
• The headers and body can be looked up in several online databases that track message checksums of verified spam messages.
• The sending system’s IP address can be looked up in several online lists of sites that have been used by spammers or are otherwise suspicious.
• Specific addresses, hosts, or domains can be blacklisted or whitelisted. A whitelist can be automatically constructed based on the sender’s past history of messages.
• SpamAssassin can be trained to recognize the types of spam that you receive by learning from a set of messages that you consider spam and a set that you consider non-spam. (SpamAssassin and the spam-filtering community often refer to non-spam messages as ham. )
• The sending system’s IP address can be compared to the sender’s domain name using the Sender Policy Framework (SPF) protocol (http://spf.pobox.com) to determine if that system is permitted to send messages from users at that domain. This feature requires SpamAssassin 3.0.

Most of SpamAssassin’s behavior is controlled through a systemwide configuration file and a set of per-user configuration files. The per-user configuration can also be stored in an SQL database.