Introduction | Installation | Status Window | General Preferences
Virus Preferences | Spam Preferences | Logging | Winnow
Training Addresses | Whitelists/SpamTraps

Documentation - Introduction

Counteragent 2 provides your EIMS Server X installation with effective and easy to maintain virus and spam scanning. The goal of Counteragent 2 was to make it as easy to use as possible while still leveraging the power of the open source mail scanners ClamAV and SpamAssassin. Counteragent is only supported on both PPC and Intel Macs.

The Mail Flow

A modified version of Glenn Anderson's Interceptor Filter X passes email from EIMS to Counteragent. Messages that are exempt from scanning are given directly back to EIMS for delivery, thus bypassing the messages that are queued for scanning. When used in conjunction with the "Don't Scan SMTP Auth Mail" and "Don't scan EIMS Authorized Relays" preferences, this allows your outgoing mail to go out immediately.

Messages are queued up for the virus scanner process within Counteragent. Counteragent then uses multiple parallel ClamAV processes to check email for viruses. By using the multiple ClamAV processes, Counteragent is able to maintain a good throughput because larger messages that may take longer to scan do not prevent smaller messages from getting scanned and moving on. Smaller messages are able to "go around" larger messages that are still being scanned. Messages that are found to be infected are handled according to the Virus Preferences.

After completing the virus scanning, clean messages are queued up for the spam scanner process. Counteragent then uses multiple parallel SpamAssassin processes to check email for spam. Again, this allows Counteragent to maintain a good throughput because larger messages that take longer to scan don't clog up the process. Smaller messages are able to "go around" larger messages that are still being scanned. Spam messages are then handled according to the Spam Preferences. Messages that are not spam will have SpamAssassin headers added to them showing how they scored and what rules effected that score. SpamAssassin uses a Bayes database that learns as it goes and becomes more accurate at recognizing spam over time.

Mail that has made it through the scanner processes is then passed back to EIMS for delivery.

Introduction | Installation | Status Window | General Preferences
Virus Preferences | Spam Preferences | Logging | Winnow
Training Addresses | Whitelists/SpamTraps