A system to block spam e-mail was implemented by the University of Wisconsin Division of Information Technology this week. WiscMail users, including faculty, staff and students, were invited to begin implementing spam-filtering technologies.

Several thousand students have already signed up to use the WiscMail filtering service. DoIT spokesman Brian Rust said student feedback is mostly positive.

“It’s working for people,” Rust said.

He added that users should start by filtering spam at about a medium level and monitor the Junk Mail folder in order to make sure no legitimate e-mail is falsely identified as unwanted.

The amount of spam processed by the system each day makes up for about 40 to 50 percent of total aggregate e-mail received, a figure that becomes more significant as total e-mail traffic within the university increases.

Last month, the university e-mail system reached an all-time peak by processing about two-and-a-half million messages in a single day.

“We just realized we needed to do something; the mail system was getting overloaded,” Rust said.

A new set of software tweaked and installed by DoIT complements the current Sun Microsystems iPlanet mail-server software already in use.

The software assigns incoming messages a spam rating, representing the likelihood that a message is unsolicited or unwanted. The spam rating, included in the message headers of every e-mail processed by the system, is then interpreted by WiscMail’s filtering service and blocked or allowed through, according to a user-defined setting.

Incoming mail is evaluated on several criteria, including the number of recipients, whether or not the message sender has a legitimate address and the actual font and body of the message.

The filter also identifies characteristic keywords and phrases included in most spam. For example, a message containing the phrase “FREE OFFER” in a large, yellow font sent to several hundred users and originating from an unconventional e-mail address would most likely be assigned a high spam rating by the system.

Users can choose how discerning the filter monitors their WiscMail web e-mail inbox by modifying several settings online. Depending on settings put in place by users, spam e-mail is redirected to a Junk Mail folder or allowed to remain in the user’s inbox.

A simple Junk Mail Filter option allows users to choose a setting, varying from high to low. A high setting will apportion the highest percentage of possible spam to the Junk Mail folder, a low setting only the most obvious and identifiable spam.

Users can also create “blacklists” and “whitelists,” containing e-mail addresses or domain names that will always be denied or allowed by the filter, respectively, regardless of their individual spam ratings.

For users not using WiscMail’s online web mail interface, filtering instructions are specific to individuals’ e-mail clients and available from DoIT’s website.

DoIT wanted to make sure the system was not a forced option for students. Therefore, the system allows students to block spam but does not directly censor students’ e-mail, especially those e-mails that might falsely be identified as bulk e-mails, Rust said.