SpamAssassin in most circumstances is very reliable. When SpamAssassin is used as a daemon, email clients call spamc. If the spamd daemon is not running, then spamc will not tag email and spam emails would be delivered to the users' mailbox. If the email solution relies on SpamAssassin, then we should regularly confirm that spamd is running. One common reason for a service outage is that the daemon has stopped. Daemons can be tested by connecting to the port that they listen on. This involves writing a test client or using an existing client in test mode. This approach can be complex. Another solution is to simply test that the daemon is running among the processes on the system.

Large companies may use products like IBM's Tivoli or HP's OpenView for systems management, and these can be extended to watch the appropriate processes and send an alert in one of many ways. For smaller companies, the cost of a product like these is prohibitive. One inexpensive...