Very fast scanning.
Excellent first line of defense at the mail gateway.
SummaryCloudmark Authority runs on Linux, hooking the Milter interface of Sendmail to parse each message prior to delivery. Installation is relatively complex if you are used to wizard interfaces on Windows – the sendmail.mc configuration file must be edited by hand, compiled into .cf form and the service restarted. But those with Sendmail experience will find it easy and the documentation goes into enormous detail.
Downtime is worth comparing. Many Windows products required two reboots, resulting in the entire server being offline for several minutes. In contrast, the Sendmail restart took less than half a second, affecting no other services at all.
A single configuration file controls all basic functions and we were concerned that, in its shipping form, the file is world readable and contains the admin password in clear text – a disastrous oversight. Spam rules are also in text files but the product has a web GUI to manage rules and quarantine.
The GUI is simple but perfectly adequate. A counter keeps track of how much money your organization has saved (according to factors supplied by the user), which is functionally pointless but the feedback managers love so you might find it handy when pushing for funds.
Spam scores are assigned according to the usual rules and a number of thresholds can be set corresponding to the score each message receives. Each threshold then has a single action associated with it, to delete or quarantine the message. This limits the functionality a little but for everyday use it is fine. Control over actual scoring is not available to the user, which could cause problems for organizations needing greater flexibility.
In action, the filter is blazingly fast. The software chewed through several thousand test messages with almost no discernable impact on sendmail and no queue backlog.
Users can manage their quarantined messages online though the interface is clumsy. Only 25 messages can be deleted at a time and one is a lucky user if he is not getting more spam than that.
If you have a sendmail gateway, this would be an excellent first line of defense. For added flexibility, you may want additional protection.