The Spam Filter

Web-Based Email includes leading-edge Spam Xploder spam-filtering technology. The spam filter is built to intercept incoming bulk mail and automatically route it to the "Bulk Mail" folder.

About Spam Filtering

Spam filtering is the concept of detecting and intercepting unwanted bulk mail before it reaches a recipient's mailbox. Generally, spam filters detect bulk mail through the occurrence of certain phrases and known spammer IP addresses in incoming mail. Because distributors of spam are increasingly innovative in their efforts to circumvent the spam filters that protect email users' mailboxes, spam is a moving target, and developers of spam-filtering technology are constantly being challenged in their quest to keep the bulk-mail onslaught at bay. Thus, in order to effectively shield email users from spam, a spam filter must be flexible.

How the Spam Filter Works

Web-Based Email's Spam Xploder spam filter screens incoming mail at the server level. Through the Web-Based Email interface you can train the filter, thus gradually improving the filter's ability to detect incoming bulk mail.

The spam filter compares a message to the user-defined black and whitelists. Whitelisted messages are allowed to pass through the filter. Blacklisted messages are treated as spam and routed to the "Bulk Mail" folder. Messages that are neither white- nor blacklisted undergo a rigorous analysis that will determine whether the message should be classified as spam. By marking messages for spam analysis, Web-Based Email users can train the spam filter. In this context, "analysis" is the process of statistically analyzing the contents of a message to improve the "intelligence" of the spam filter. Thus, as more messages are marked for spam analysis, the filter gradually improves its ability to detect and intercept incoming bulk mail.

Training the Spam Filter

Training the spam filter is the process of submitting email messages for spam analysis, thus gradually increasing the "intelligence" of the spam filter. That way, as the spam filter, compiles data it will become increasingly adept at detecting incoming spam.

To train the spam filter, you can mark a message as either "spam" or "not spam."

• Messages selected for training are passed to the server, along with a flag indicating whether the message should be considered spam or good mail. These messages undergo a content analysis similar to the statistical filter. The message is broken into tokens. Tokens are added to a list and counted. The list of tokens and counts is then analyzed.

• The analysis consists of comparing tokens found in the message against the user dataset. Each token is searched for in the user data. If a token from the message is found in the user dataset, the previous spam and good mail counts for that token are retrieved. The counts are updated based on the spam/not spam flag, and the new spam probability is calculated for the token.

• If the token is not found, a new record is added to the user dataset for the token, and the spam probability is calculated.

The spam filter's user data evolves and grows as more messages are analyzed. More tokens are added, and the probability scores are refined until the user has a well-defined set of personalized tokens commonly found in this/her incoming bulk and good mail. This adaptive scoring ensures that each user has a different definition of spam and good mail, thus making it very difficult to distribute mass mailings that evade the recipients' individually configured spam filters.

This personalized, adaptive approach guarantees fewer misclassifications of mail, as each user teaches the system his/her personal definition of what constitutes spam and good mail.

How to mark a message as spam?

To mark a message as spam and thus submit that message for spam analysis, either:

• Select the message(s) from the mailbox list; then, from the "Apply This Action ... " drop-down menu, select "This Is Spam."
  Or,

• Open the message; then in the message window click the "Mark as Spam" button.

This will initiate the spam analysis process.

The "Mark as Spam" button

Clicking the "Mark as Spam" button within a message window will initiate the spam analysis procedure for that message. When the analysis is complete the message will be moved to the "Trash" folder.

About the Spam-Filtering Strength Setting

The Spam Xploder spam filter allows you to customize the filter's sensitivity to incoming bulk mail by changing the "Spam Filtering Strength" level. There are five settings: "Very Low," "Low," "Medium," "High," and "Very High." The higher the strength level, the more incoming mail will be considered spam by the filter. By default, the spam-filtering strength is set to the "Low" setting. You can change the setting via the "Spam Settings" Web-Based Email menu item.

If you do not know which strength level suits you best, you can experiment with various settings until you find one that suits your personal preference.

How the Spam Filter and Black-/Whitelists Are Connected

When you mark a message for analysis, the spam filter will first check whether that message is featured on either of your black- or whitelists.

— Mail from blacklisted senders is always treated as bulk mail by the spam filter. Blacklisted mail is thus automatically routed to the "Bulk Mail" folder.

— Whitelisted mail is always allowed to pass the spam filter.

If the mail is neither black- nor whitelisted, the statistical spam analysis will proceed to the next step in the process.

Spam Settings

Detect and redirect junk email (bulk mail) by activating or deactivating the Spam Xploder spam-filtering feature. As well, use this feature to review and manage your black- and whitelists.

Use the "Spam Settings" window to set up the filtering measures (i.e., whether to detect and filter known spam, and how to handle detected spam). By default, the spam filter will route detected spam to the "Bulk Mail" folder. However, if so desired, you can elect to instead have Web-Based Email mark intercepted bulk mail with "SPAM" in the mailbox.

Additionally, the Spam Xploder spam filter allows you to customize the filter's sensitivity to incoming bulk mail by changing the "Spam Filtering Strength" level. There are five settings: "Very Low," "Low," "Medium," "High," and "Very High." The higher the strength level, the more incoming mail will be considered spam by the filter. By default, the spam-filtering strength is set to the "Low" setting. You can change the setting via the "Spam Settings" Web-Based Email menu item.

If you do not know which strength level suits you best, you can experiment with various settings until you find one that suits your personal preference.

Blacklist

A blacklist is a list of email addresses and domains from which you do not want to receive email communications. Incoming mail that fits the blacklist criteria is treated as spam/bulk mail and routed to the "Bulk Mail" folder.

The blacklist is automatically enabled.

— To add a sender to the blacklist, select a message from a mail folder; then, from the "Apply This Action " drop-down menu, select "Blacklist Sender" or "Blacklist Domain." You can also add an entry to the blacklist by typing in the address in the address in the "New Address" field and selecting "Blacklist" from the drop-down menu. Click "Add" to add the address to the blacklist.

— To remove a sender from the blacklist, select a message from that sender; then, in the "Spam Settings" menu, click "Remove Checked Addresses."

Whitelist

Web-Based Email enables you to specifically identify and list email senders and domains from which you will always accept email. This list is called your "whitelist." Whitelisted mail is always allowed to pass through the spam filter.

— To add a sender to the whitelist, select a message from a mail folder; then, from the "Apply This Action …" drop-down menu, select "Whitelist Sender" or "Whitelist Domain." You can also add an entry to the whitelist by typing in the address in the address in the "New Address" field and selecting "Whitelist" from the drop-down menu. Click "Add" to add the address to the whitelist.

— To remove a sender from the whitelist, select a message from that sender; then, in the "Spam Settings" menu, click "Remove Checked Addresses."

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