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Spam Filtering
ITS has added spam filtering functionality to the central e-mail server to address the increasing volume of unsolicited commercial e-mail messages (UCE, commonly referred to as spam) being received by members of the University community. The spam filtering functionality is provided by a free software package called Spam Assassin which runs on the mail server, and is available on an opt-in basis to all staff and students.
How does it work?There is no definitive, 100% accurate method to distinguish between spam and non-spam messages sent via e-mail, due to the variety of methods used to disguise spam. The current best practice for identifying spam messages is for software to analyse each incoming e-mail message and allocate a points score based on text patterns matching known spam. If the points score exceeds a set threshold, the message is marked as spam. This means that it is possible for UCE to not score enough points to be tagged as spam, and also for a small percentage (less than 1%) of legitimate e-mail messages to be marked as spam. For this reason, messages marked as spam are not deleted automatically before reaching mailboxes. Instead, once you have opted in to having your e-mails filtered, messages which are identified as spam will be placed into a mail folder named "Spam" rather than going into your Inbox. If a folder named "Spam" does not already exist in your account, it will be automatically created the first time a message is marked as spam. The messages in this folder can then be checked periodically to see whether any legitimate e-mails have wrongly been marked as spam. Spam Assassin also has the capability to "learn" from e-mail messages, which allows it to identify words and phrases which are commonly used in spam messages and improve its accuracy in detecting spam. In order to analyse each message, Spam Assassin performs a range of tests which typically will take less than ten seconds, however this causes delivery of e-mail messages into your account to be slower than if no filtering was used. How do I opt in?As some staff and students do not receive any spam and do not require filtering to be set up for their account, you will need to opt in to the spam filtering. To enable spam filtering for your account, log in to Web Mail, click on the Account Manager link at the top of the screen, click on the Spam Filtering link, click on the checkbox labelled "Enable spam filtering for your e-mail account", enter your password at the bottom of the form to confirm that you want to activate the spam filtering for your account, and click on Submit.
How do I check the contents of the Spam folder?In Web Mail, the drop down menu on the top right of the screen lists the folders which are present on the mail server. If you do not have a Spam folder, you have not received any e-mail which has been tagged as spam. In the standard desktop mail client (Netscape Messenger), click on File --> Subscribe which will list all folders on the e-mail server which you have access to. This may take a few minutes to complete.
 If the Spam folder is listed but does not have a tick under the Subscribe column, click on the Subscribe column next to the Spam folder name so that it is ticked, and click on the OK button at the bottom of the window. Please note that any messages stored in the Spam folder, like messages stored in all other mail folders in your account, count towards your mail quota and should be cleaned periodically to avoid going over quota and potentially preventing you from receiving future e-mails. For how long will messages stay in the Spam folder?Messages in the Spam filter are removed 30 days after they were received. How do I check that my messages are being filtered?You can check whether or not a message has passed through the spam filtering by looking at the headers of the e-mail message. To see the headers when viewing a message, in Netscape press Ctrl-U to view the message source, or in Web Mail click on the Message Source heading. If the message has X-Spam-Status headers just before the start of the body of the e-mail, it has passed through the spam filtering. The X-Spam-Status header will also tell you how many points the e-mail has scored and how many points it needs to score before being considered as spam. I've received spam which was not correctly identified by the filtering!Individuals responsible for spam constantly use new techniques to try to evade spam filters such as Spam Assassin. Some examples include strings of random words in the spam, intentionally misspelling words, substituting numbers for letters, random use of punctuation in words, and inserting valid words in the middle of other words. If you are receiving spam which is scoring below the points threshold, you may wish to adjust the points score which applies to messages sent to your e-mail account. To do this, follow the Account Manager link within Web Mail, click on Spam Filtering, and enter a points score into the "Points threshold" box. A higher score than the default of 5 will mean that less messages sent to your account will be tagged as spam, and a lower score will mean that more messages will be tagged as spam.
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