DoC Computing Support Group


Revision 1 as of 2008-09-11 11:05:21

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Email Spam Filtering

What is the Spam problem, and what is BrightMail?

In recent years, unsolicited bulk emails (spam) have become an increasing problem. Many people are finding their inboxes flooded with increasingly offensive spam - perhaps 100 spam messages per useful message.

Dealing with this problem is quite tricky, because there is no objective definition of what precisely constitutes a spam email, and thus the problem of taking an email message and reliably categorising it as spam or non-spam is a hard problem, with no single perfect solution. However, this problem is receiving serious attention world-wide nowadays, and several systems are now available which use a variety of techniques to detect spam.

CSG have investigated several spam-detection techniques - SpamAssassin and Dspam in the past - and have now settled on a commercial anti-spam and anti-virus package called BrightMail from Symantec. BrightMail automatically downloads new anti-spam and anti-virus tests - updating itself every few minutes - and claims to largely solve the spam problem by detecting the bulk of spam mail - but not all - while having an astonishingly low 1-in-a-million false positive rate.