Canned Spam Filters

Are you interested in an "Incredible Satellite TV offer?" Would you like to "Consolidate your debts in an offshore Visa card?" No? Well then, certainly you'd like to "Dig up Dirt on your Coworkers!" Still not interested? Then read on; you may be interested in the ACCC's new automatic spam filtering system.

You've probably seen phrases like those above in email messages you received but didn't request, that is, spam. We discussed the spam problem in the October/November/December 2000 issue of the A3C Connection in the article called "Slamming Spamming." That article covered the basics, what spam is, how it works, and some possible options to minimize the amount of spam you receive.

One such option is to filter out spam automatically. But a problem with automatic antispam filtering is that such filters can be very complicated to set up, and they can dispose of valid email if not crafted carefully. We have tried to remedy this by providing an automatic and simple way to set up effective antispam email filters, i.e., Canned Spam Filters.

While the Mailtools antispam filter will probably catch most of the spam mail you receive, it won't catch all of it -- a perfect antispam filter is impossible. Some spam will inevitably slip by, so you can't forget where your Delete key is yet, but hopefully your clicking finger will get much less work with this filter in place.

Likewise, although we have taken care to make this unlikely, it is also possible that a valid piece of email will somehow be sorted in with the spam, so you should check through your filtered spam messages from time to time to make sure you didn't miss anything that you wanted to see -- the notification of your lottery winnings, for example.

To set up your own antispam filters, visit our Email Tools Web utility, login, and select your email server if necessary. Select Create a new antispam filter.

Setting up the antispam filter is done in three steps. The first two steps must be done accurately to avoid legitimate email from being filtered out as spam.

Step 1: Enter any email addresses that you use other than to your normal UIC email address (or addresses -- your netid at host name that ends with uic.edu). For example, you may have an account such as imah@example.com, which simply forwards mail from there to your UIC account. In this case, enter imah@example.com into the box in Step 1, it will prevent messages addressed to you there as being counted as spam.

Additionally, you may have a departmental alias at UIC that simply forwards mail to you. If you get mail sent to latinverbs@uic.edu, for example, then entering that address here will tell the filter that it is valid email and should not be sorted as spam.

Step 2: To prevent messages from email discussion lists from being counted as spam, type the email address of all lists to which you are subscribed in the box, not including any here at UIC -- UIC lists are automatically excluded from the filter. For instance, do you subscribe to bubblegumweekly@stickylists.com? Then you'll need to put that address into the box in Step 2.

Of course, if you forget to identify any of your alternate email addresses or email discussion lists, the filter will identify messages to them as spam, so you'll want to be sure to check your spam folder frequently at first to see if any messages got through from lists you forgot to include. You can imagine that, if you subscribe to many lists, it may take a few tries before you get it quite right.

Step 3: If you use WebMail, pine, or Eudora or another personal computer email program with IMAP, you'll probably want to choose the action File this message into my spam folder. Thus, once an email message is identified as being spam, it will automatically be sorted into another folder on the server called spam, which you should check at your leisure and delete the messages that are really spam.

That's it! Just click the Create Antispam filter button below Step 3 to begin your no-spam diet.

If you'd like to know how the antispam filter works, see How the Mailtools Filters Work.

You can still use the Mailtools ready-made antispam (and attachment) filter, using the other action option, Tag only:. This action adds a hidden tag to each spam email message. (What they actually add is an X-header ; see the online version of Figure 2: Headers of a Legit Email Message, from the October/ November/ December 2000 A3C Connection.)

You then use this hidden tag as a criterion in a Eudora local filter so that Eudora will recognize the email message as spam and move it into a local spam mailbox on your personal computer. Figure 1 below is a Eudora filter that will do that.

Did you forget to add an email discussion list? An off-campus address? No problem. Just return to Email Filters page and jump down to the section where you created the antispam filter. There you'll see that the alternate addresses and off-campus lists that you entered before appear in the boxes where you typed them. Simply edit the lists and click the button again and your changes will take effect immediately.

Comments are welcome; please send them
to Joshua Frigerio, joshua@uic.edu