Due to the growing problem of spam (generally defined as unsolicited and unwanted commercially oriented e-mail), mail.sas users can now opt in to a system which can help to limit the amount of such mail that they will receive in their inbox. Our system (relying on SpamAssassin) works by scanning each message for certain characteristics (e.g. subject heading in all capital letters, references to free or no cost offers, lack of actual user name in From header), each of which is assigned a specific score by the system. If the total score for a message exceeds a certain threshold, the message will be considered to be spam and will be placed in a special folder. More information about the characteristics that add or subtract to the value assigned to a message can be found here.

Since there is no perfect way to detect spam, some legitimate messages may be marked as spam when they are not. This is called a false positive. Messages from listserves or other automated mailing systems may be most likely to result in false positives.

Mail.sas offers a two tiered filtering solution. Any message scoring above 10 points will not be accepted by our mail server - notifying the sender that the mail appears to be spam. Messages scoring below 10 points will be directed to the user's mail spool. At this point the second tier of filtering is enabled by each user, who can pick from six predefined levels of protection. A higher level of protection means that more actual spam will be identified, but will also tend to increase the rate of false positives. After opting in to the spam filtering system, you will need to occasionally check the folder where the messages identified as spam are placed to determine if any of the messages are ones you would actually like to receive, and to delete any messages properly identified as spam. If there are too many false positives, it may make sense to select a lower level of protection. You may have to experiment a bit to see which level of protection works best for you. Messages left in your spam folder will be deleted after two weeks, so you should check at least weekly.

On mail.sas, messages identified as spam will be placed in to a folder named "caught-spam". This folder will be placed in the user's home directory within the subdirectory "Mail" in most cases. Pine users can select to have it placed in the "mail" (lowercase "m") directory, since Pine uses this directory for mail folders by default. The "caught-spam" folder can then be accessed just like any other mail folder stored on the mail.sas server.

Users of elm or mutt can switch to the folder using the "c" command to change folder and then entering "=caught-spam" (no quotes should be used). Anyone using an e-mail client such as Netscape, Eudora, or Outlook in IMAP mode will be able to access the caught-spam folder just as they can any other folder that is stored on the server. When using webmail.sas, the folder can also be accessed by selecting it from the list of folders shown in the drop down box upper right hand corner.

Those using such e-mail clients in POP mode (where mail is downloaded from rather than stored on the mail.sas server) will have to use another method to view the caught-spam folder, because POP clients can only access the inbox folder on the server. Since the caught-spam folder will only have to be checked occasionally, use of webmail.sas may be the best way for these users to view the caught-spam folder.

To change your spam protection settings, select the appropriate level of protection, indicate if you use Pine, and click 'Update spam protection'.

After enabling spam protection, remember to check your caught-spam folder occasionally for any false positives among the messages identified as spam, and to delete any messages properly identified as spam.

Messages left in your spam folder will be deleted after two weeks, so you should check it at least weekly for any false postives.

If you will be away for a vacation, you may want to disable spam protection to ensure you don't have any false positive messages deleted while you are away.

To opt in to this system, students or others with accounts on Mail.SAS should go to the Mail.SAS Account configuration page. After logging in, select the Spam Filtering option from the services available.

SAS faculty and staff who have migrated to the facstaff.sas server should instead go to the Facstaff.SAS Account configuration page and then select the Web Account services link, log in, and then select the Spam Filtering option from the services available.

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Last modified: Friday, 09-Feb-2007 11:56:24 EST