Tumbleweed Communications' MailGate Edge has been designed to protect your mail system from attacks, rather than filter all your email traffic to detect the presence of spam.
With a 1U-height rack-mountable chassis, it offers one Ethernet port, a status screen and a six-button control cluster to configure its IP address, subnet mask and default gateway address.
Further set-up and administration is via a web browser, while the display shows operational information.
The administrative interface is uncomplicated, with a wizard to guide you through the rest of the configuration process.
The system provides several ways to defend the corporate mail system, from simple block lists to more complex Directory Harvesting Attack (DHA) and Denial of Service (DoS) defenses.
You can restrict mail traffic characteristics such as maximum message size and number of recipients per message.
It will reject connections from other servers if the request appears to be suspicious, while administrators can add entries to its block list, which is also updated automatically by the DHA and DoS defense systems.
Individual blocks can set up to last any length of time.
As well as these general protection features, the system's DHA and DoS systems will detect and react to attacks automatically, and can be tuned to meet specific circumstances.
These features do have to be enabled by an administrator, but we feel that it would be better if they were enabled by default.
Both systems monitor and analyze mail traffic, looking for unusual usage patterns. In the case of a DHA attempt, the primary characteristic is an excessive amount of messages addressed to non-existent recipients from any one host.
Once a DHA attempt has been detected, the originating host is then automatically placed on the block list.
The DoS system functions in a similar way, in this case based on the volumes of traffic from individual hosts, but the system lacks flexibility.