Incoming Mail Gateway Servers Upgraded to Speed up Email Traffic

by Henry Wong
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University Email

You may have noticed that, since the end of last month, you have been receiving email from your external correspondents in only a matter of seconds. This is the result of the recent system upgrade performed on the university incoming mail gateway.

Spam/junk email had been the headache of email users and email administrators for many years since electronic mail became popular. The number of spam email is steadily increasing every year. Nowadays 80% to 90% of email delivered over the Internet is spam. (ZDNet: In Asia Pacific, roughly 91.8% of all emails are spam).

The implementation of “drop the email if its spam-level detected is 99% or higher” policy (adopted by the Committee on Information System and Technology (CIST) in December 2006) had significantly reduced spam email delivered to our user mailboxes. However, the proliferation of spam email had caused our incoming email gateway servers to be more and more overworked in filtering spam email and delivering the legitimate messages to our users. In the past few months, our mail gateway had been bombarded with an increasing number of spam email, causing hours of delay in its external email delivery.

To tackle the situation, the Computing Services Centre (CSC) has upgraded the existing email gateway servers as well as installed a brand new high-powered email gateway server, employing a collection of newer state-of-the-art anti-spam technologies that include IP reputation, advanced keyword analysis, and MTA IP blocking etc. Many spam email, once identified to be originated from suspected spam source (in particular the Botnets, networks of virus-infected computers being used to send 80% of spam nowadays) by one or more of these technologies, will be rejected by our servers, hence much reducing the number of email queued up on the server for spam score calculation. This results in great saving of our network/system resources and profound improvement in processing speed. Our observation shows that the delay time for delivering external incoming email to our users was significantly reduced from 1/2 hour -1 hour on average to 10 second - 1 minute.

The CSC will continue to monitor the server performance and to maintain an outstanding email service for the university community.