Slamming Spam: A Guide for System Administrators

Intelligent Message Filter

IMF is a plugin provided by Microsoft that greatly improves Exchange 2003’s spam fighting capability. Microsoft doesn’t give the administrator the ability to allow users to retrain the filters like you can in CRM114 or bogofilter, but IMF is still very useful.

Microsoft uses a concept known as the Spam Confidence Level (SCL) to determine whether or not a particular message is spam. Each message is scored with an integer value from 0 to 9, with 0 indicating a non-spam message. Values from 1 to 9 indicates a spam message, with a lower number indicating that a message is likely not spam and a higher number indicating that a message is probably spam. Each message is scored, and then depending upon its score, the message ...