Fresno State e-mail spam filter information

Overview

This document is intended to provide information on the updated spam filter capabilities that the ITS department will be delivering to Fresno State students, faculty and staff, and to our CVIP email customers, on March 16, 2005.   While our existing spam filters have provided some relief from the problem of unsolicited bulk email (spam), continued improvements are necessary as we work to limit the impact that these nuisance messages have on the members of our University community.   Please refer to the material below to gain a better understanding of the changes we will be putting in place and how they will affect users of the campus email system.

What changes is ITS making to the university’s spam filters?

There are three major changes that ITS will make with this spam filter update.   We will be:

• Implementing improvements to our existing SpamAssassin system.
• Implementing an opt-out policy under which every user of the university email system will have the spam filter turned on by default.
• Adding a spam-rejection capability based on Real-time Black-hole Lists (RBLs)

More details on each of these changes are provided below.

When will this change take place?

The new system will be activated on Wednesday, March 16, 2005.

Who will be affected?

All users of the Fresno State email system, students, faculty and staff, and all our CVIP email customers.

How will they be informed of this change?

We will be using a variety of communications mechanisms to alert our users to this change.   Please see the Communications Campaign section below.

Where can users go to get assistance in using the new system?

The campus Help Desk is preparing new web-based documentation that will be available to assist users in configuring and using the new spam filters, or in deactivating these filters, if they wish.   Users will also be able to call the Help Desk for assistance.   A link to this new information will be provided in communications to email users.

What will these changes mean for users of the university’s email system?

The improved spam filters should result in users receiving substantially less unsolicited email, and less time wasted dealing with these unwelcome messages.   Here are details on each of the changes that we are making:

Implementing improvements to our existing SpamAssassin system.   These improvements include:

• a more accurate system for identifying messages as spam
• improved performance to ensure that messages are processed and delivered more quickly
• the ability to have messages deleted automatically if they have a high spam score
• the ability to maintain a “white list” of email addresses for correspondents whose messages you never want treated as spam.
• An improved web page that can be used to set your SpamAssassin options.   A picture of this new page is included later in this document.

As it has in the past SpamAssassin will continue to facilitate spam filtering by using a set of rules to determine how likely each message is to be spam and assigning a “spam score” to the message that allows appropriate action to be taken.   Users will still have the option of having messages that are classified as spam left on the email server in a folder named “Bulk-Email”, or having these messages scored and delivered to the email client they use on their workstation.

Please Note: Existing users of SpamAssassin will notice two changes in the way that SpamAssassin processes spam messages.   First, each message identified as spam will no longer be delivered as an attachment to another message listing the specific spam tests that contributed to the spam score.  Second, for those users who elect to leave their spam messages on the server, the folder where these messages are stored will be named “Bulk-Email”.   If you have been using another name for your spam folder on the server, please be aware of this change.

Implementing an opt-out policy under which every user of the university email system will have the spam filter turned on by default.

In order to ensure that everyone has the opportunity to benefit from the improved SpamAssassin filtering capabilities, we will be turning on spam filtering for every student, faculty, staff and CVIP email account.   Of course, anyone who would prefer not to use this service may deactivate it in less than a minute by using the new web interface.   For users who are already using SpamAssassin, we will migrate their existing spam filter settings into the new system.

The default settings for the users who have not used SpamAssassin in the past will identify most spam messages, delete messages that score very high and are obvious spam and store the other spam messages on the email server in a separate “Bulk-Email” folder for each user.   Users will be able to review the messages left in this “Bulk-Email” folder by using the web-based email system at http://email.csufresno.edu.

These default settings are designed to catch as much spam as possible while making it unlikely that legitimate messages will be accidentally treated as spam.   These settings will provide good spam filtering for users even if they don’t make any changes to their filter parameters using the web interface.   Users will also be able to use the instructions provided later in this document to make their spam filters more effective by increasing their sensitivity and maintaining a personal “white list”.

Adding a spam-rejection capability based on Real-time Black-hole Lists (RBLs)

In addition to the improved SpamAssassin system, we will begin using the Real-time Black-hole List system to reject email messages that are sent from well-know sources of spam.   Any message that is rejected will be returned to the sender with information on how to correct the problem.   As this RBL filter processes all email directed to the University’s email servers, individual users will not be able to deactivate it for their email accounts.   We have tested this new capability with our CVIP email users for several months and it has provided excellent service.

How can users customize or adjust their spam filters?

To customize or adjust their spam filters, users should use a web browser, like Internet Explorer, to access http://email.csufresno.edu or log in to their email from http://www.cvip.net.   Once logged in the user should click on “Options” in the menu bar at the top of the page to display the “Options” page.   On the “Options” page, the user should select the “Spam Filter” item in the menu column at the left side of the page.   Selecting “Spam Filter” will display the web page shown on the next two pages of this document.

On this page, the user can:

• Turn spam filtering on, or off
• Adjust the strength of their spam filter
• Choose whether to leave messages on the email server, or have them delivered to an email program running on their desktop or laptop computer
• Choose whether obvious, high-scoring, spam messages should be deleted automatically
• Maintain a “white list” of email address for correspondents whose messages should never be treated as spam

Is there anything I need to do about the messages that are left on the server in my “Bulk-Email” folder?

You should use the web-based email interface at http://email.csufresno.edu to review the messages left in this folder from time to time to ensure that no legitimate email message has been incorrectly classified as spam and set aside in this folder.   If you do find a legitimate message in your “Bulk-Email” folder, we suggest that you move the message to your “Inbox” folder on the server and use the “Spam Filter” interface from the “Options” page (described above) to add the address of the sender to your “white list” so that no future messages from this correspondent are classified as spam.

You can delete the messages from your “Bulk-Email” folder whenever you’d like.   If you leave messages in the folder for more than 30 days, they will be deleted for you.

How can I be sure that the greatest number of spam messages are trapped by the new filters?

To improve the effectiveness of your spam filter, and have it trap more spam, we suggest that you:

• Use the web interface described above to increase the strength of your spam filter
• Review the messages added to your “Bulk-Email” folder frequently to identify any messages that are being incorrectly classified as spam
• Move any such messages to your “Inbox” folder
• Use the “Spam Filter” interface from the “Options” page (described above) to add the address of the sender to your “white list” so that no future messages from this correspondent are classified as spam.

As you update your “white list”, you will find that fewer and fewer messages are incorrectly identified as spam.   Over time, you will find that you only need to check your “Bulk Email” folder occasionally to ensure that no new correspondents need to be added to your “white list”.   Now your spam filter will be trapping more spam and your “white list” will ensure that legitimate messages are delivered to your Inbox.

What kind of results should I expect from the improved spam filters?

While no spam filter can ensure that you never receive unwelcome messages, we think you’ll find that our new spam filters are a significant improvement over the previous system.   The chart below will give you some idea of the reductions in spam that we’ve seen in our testing of this new system.

The new spam filter system also includes the ability to learn what messages each user considers spam.   This “Bayesian” filtering technique means that your spam filter will improve in accuracy as you use it over time.

We will continue our efforts to improve the spam filters that we provide.   As the techniques used by spammers change, we will be working to implement corresponding changes in our filters to ensure the best possible service.