Filtering Spam in Netscape Mail for Macintosh (Advanced)

Abstract

This document is designed to assist ECE affiliates in setting up mail filters to decrease the amount of "junk mail" (also known as "spam") viewed in their Inbox. This "Advanced" form of spam filtering allows you to specify the spam score that is used to filter and allows you to create rules to prevent specific e-mail messages from being tagged as "spam."

Part 1: Adjusting the spam tolerance level

UCSD's spam filtering system uses an algorithm to determine the likelihood that a given piece of mail is "spam," based on a variety of criteria. It assigns each message a score, representing the probability that the message in question is spam. UCSD's system will tag a message as "spam" if it receives a score of 5.0 or above. You may wish to select a score other than five for your filtering needs. The score is represented in the mail message graphically in the X-Spam-Level header -- the number of asterisks (*) in the line denote the " spam score." Choosing a lower value will result in a greater volume of spam being directed to your Spam folder, but it will also increase the likelihood of a legitimate mail message accidentally being sorted as spam. To determine the level at which you feel comfortable filtering, we recommend that you examine the assigned score on a variety of messages in your inbox. To view this information you will need to look in the mail headers of your e-mail, which you can do by selecting the e-mail, going to the View pulldown menu, select Headers and then click on All - the spam score usually appears near the bottom.

Use SPAM as the title of the filter. Check Match all of the following. Select Customize from the drop-down menu.

Type X-Spam-Level in the field under New message header Then click Add and OK. Now select X-Spam Level from the drop-down menu. In the text field next to Contains, type level and the number of *'s equal to the number you decided upon in Part 1.

Click on the down pointing arrow next to "Perform this action" and select Move to folder. Click New Folder and type in SPAM for the name. Select Create as a sub folder of and select your default account, then the parent option. The new Spam rule will show up in your Filters window. You may now close the window.

From now on, all incoming e-mail which appears to be "spam" will be automatically moved to the new folder you created. Note that it is possible that legitimate e-mail may be accidentally marked as spam, so it is recommended that you periodically check the contents of this folder to ensure that this has not occurred before deleting its contents.

Part 2: Creating exceptions to spam filtering for commonly received mail

If you would like to override the spam filters for a particular address (for example, if your friend gblufin@hotmail.com sends you e-mail that is constantly filtered into your Spam folder) to prevent it from being filtered out, you need to create what is called an exception rule. The following will take you through the additional steps needed to set up these exception rules.

Open up the filters window as above and select the spam filter you created. Click on Edit then click More. Change For incoming messges that: Match any of the following to Match all of the following Select the criteria you wish to filter on, in this example we'll use the sender. We wish to receive e-mail from someone with the address gbluefin@hotmail.com, so we select Doesn't contain from the dropdown box next to Sender and then put gbluefin@hotmail.com (or whichever address we don't want to block) in the box. Leave the other settings as before and click OK until you are back in the main mail screen.

From now on, all incoming e-mail which appears to be "spam" will be automatically moved to the new folder you created. Note that it is possible for legitimate e-mail to be accidentally marked as spam. It is recommended that you periodically check the contents of this folder to ensure that this has not occurred before deleting its contents.

Questions

If you have any further questions or encounter problems while attempting to set up your filter, send an e-mail message to ecehelp@ece.ucsd.edu