Spam Filtering

At the beginning of 2005, the CSR office began to filter incoming messages for spam. The spam filter was extensively updated at the beginning of August, 2009.

The department spam filter uses several tools to combat the proliferation of spam. The largest is a suite of programs called MailScanner. MailScanner makes use of the excellent SpamAssassin to assign each message sent to the department a spam score. Once all the spam and virus scanning is finished, the score is compared against a threshold to determine what kind of message it is. We have three general classifications for all messages:

High Spam are messages that have a very high spam score. The system discards these messages and they never reach an Inbox.

Low Spam are messages that have scored such that they are most likely spam, but it is still possible that the message could still be legitimate. These messages are sent on to the Inbox, but with the original message as an attachment.

Ham are messages that are believed to be legitimate email messages and delivered to the Inbox without modification.

Below is a graph showing the different amounts of High Spam, Low Spam and Ham that the department has received over the last 30 days.

30 Day Spam Graph

This is an image showing the overall breakdown of all messages received by the department mail filter.

Yesterday's Email Breakup