Spam Filter Exchange

Spam filters for Microsoft Exchange and Outlook Express are designed to block spam emails from your inbox.

Using an effective spam filter, Exchange, Outlook Express, Windows Mail, Thunderbird and other servers run much more smoothly as you do not have to spend as much time sorting through and deleting spam messages. The spam filter usually sends suspected email into a special spam folder or to the trash folder, so that the user can check to make sure no valid emails are sent there. However, some users prefer filters that simply delete suspected spam.

Types of spam filters
The spam filter server has basic methods for tackling spam email: Bayesian analysis, challenge response, rules-based filtering, and global blacklisting.

Bayesian analysis involve the use of algorithms that analyze the message content to determine whether is a regular email or spam. For this method to work, the user must “train” the system for specific types of mathematical signatures that have an individual focus.

Rules-based filtering is similar to Bayesian analysis in that the user has to “program” the filter as to the nature of spam types encountered. The user can add rules for the software to filter spam email, for example, avoiding certain spelling variations of a keyword. As with Bayesian analysis, users must be wary of not blocking valid emails.

Challenge-response only allows pre-approved emails to arrive in one’s inbox. When a user receives an email, the challenge-response system sends an authentication email back to the sender. The sender must respond to this message before the original email is approved. The main purpose of the challenge-response system is to ensure that a real person rather than a software spam program has sent the email message.

Global black lists are listings of IP or email addresses associated with frequent spamming. Such listings are often created by complaints filed by email users. Most email systems allow one to mark messages as spam – automatically alerting the email service. If enough reports accumulate, the sender may be placed on a global black list. Some spammers attempt to counter this method by constantly changing email servers.

Choosing a spam filter
Most email systems have their own spam filters, but you may want to use external software to supplement or replace your existing filter. Some users, for example, may find the Outlook Express spam filter does not handle the kind of messages that they receive.

Fortunately, there are a large number of third party solutions available on the market. Generally, one should only use software that has been tested and reviewed by reputable sources. Websites like CNET, and a large number of tech blogs, regularly review software products. Only tech savvy individuals and groups should use beta software or any software that has not been thoroughly reviewed.

Ask for references from friends, family and co-workers, especially from those who spend a lot of time using email. A good Exchange spam filter should use two or more of the methods described above: Bayesian analysis, blacklists, rules-based, and challenge-response.