Protection for CityU Email Systems to Reduce Spam and Phishing Email

by Henry Wong

As a protection for all University email users, the Committee on Information Services and Technology (CIST) endorsed in its meeting in August 2010 to enable email spam filtering as a default for all CityU email users, and it was implemented on staff, student and alumni email systems on 21 December 2010. 

The default spam filtering of level 9 (email with calculated spam score of 90% or higher will be filtered as spam) will be applied to new email accounts, and to all old email accounts which have not enabled or set spam filtering rules before.  Filtered email will be kept in the AUTO-PURGE folder of the user’s mailbox for 1 month where the user should check regularly for any mistakenly filtered email.   Users can adjust the spam filter level of his/her email account, and add whitelist and blacklist to complement the auto-filtering as needed. 

Please see the Appendix for background on email spam filtering in the University, and refer to the details on spam filtering. 



Since 2006, the CityU has deployed a popular email anti-spam filtering tool and has enabled basic spam filtering for staff, student and alumni email systems. This has reduced the volume of spam email by two-third, and for optimal anti-spamming result, users are encouraged to further enable spam filtering in their email accounts and adjust the filtering level according to the amount of spam email received (users with popular email address prefix or actively engaging in social networking and web services with their email accounts may receive more spam email).  However, almost 75% of staff and 90% of students and alumni have not enabled spam filtering, and this not only degrades day-to-day email communication for studies and work as spam and phishing email is intermixed with the normal one, but also exposes themselves and the University to spammers and hackers.


1.      What are email spam filtering, spam level, whitelist and blacklist?

2.      How can I adjust spam filtering level and set up whitelist and blacklist?

3.      Where can I find the messages filtered by spam filtering?