Enhanced Junk Mail Filtering Service

by Clevin Wong

Spam, or junk mail, refers to unsolicited commercial email (UCE) and unsolicited bulk email (UBE). It is an annoying problem faced by most of the email users. In order to provide better spam filtering service, CSC has upgraded the "spam scanner" software from SpamAssassin to Sophos Pure Message recently.

Spam scanner is a piece of software used to evaluate the "spam-level" of each external email to indicate its likelihood to be a spam. It does not delete any user email. Instead, it only adds a special header on each email to indicate its spam-level. A user can utilize the "spam auto-filtering" function to filter the junk mail according his/her threshold on the spam-level.

The new spam scanner has the following enhancements:

  • As spammers are becoming more sophisticated in mixing their spam in with regular email, patterns of spam are rapidly evolving. Hence, the effectiveness of a spam scanner software is directly affected by the update frequency of the spam information. One of the major advantages of Pure Message is that it updates the spam information every hour.
  • Pure Message is a licensed commercial software, its source codes are confidential. Hence, spammers cannot study its source codes and devise "work-around mechanisms" to exploit the program's weaknesses and fool the software.
  • Owing to the collaboration between Sun Microsystems and Sophos, the Sun's mail server can be integrated with Pure Message to defend against spam. The integrated solution enables the mail server to communicate directly with the spam scanner via a native channel architecture without adding extra layers of communication overhead thereby optimizing its performance. Neither does the solution require a third-party message transfer agent to broker the communication.
  • Moreover, Pure Message has integrated functions of both anti-spamming and anti-virus on the same software. Thus, effectiveness and efficiency are enhanced.

For existing users of the "spam auto-filtering" service, they can enjoy the advantages provided by the upgraded spam scanner automatically. If you want to learn more about this service, please refer to the user guide at http://email.cityu.edu.hk/faq/spamfilter/usrguide.htm .


  1. The Apache SpamAssassin Project