IronPort Systems and Tumbleweed Communications separately are targeting corporate customers with network appliances designed to manage e-mail traffic and fight spam.

IronPort next month is scheduled to ship its new C60 appliance with a combination of the company's high-speed messaging gateway and Brightmail's Anti-Spam software.

Also this week, Brightmail is set to release Version 5.0 of its spam-blocking technology, which features the ability to identify spam based on URLs embedded in messages, near real-time creation of blacklists and a new signature technology that extracts random characters from e-mail to expose messages as spam.

IronPort's C60 gateway, which comes in a 2U chassis, and has a policy-management engine and Mail Flow Monitor. It also has a spam-blocking engine that employs Brightmail's Probe Network to increase accuracy, and perform content and source filtering on e-mail before it reaches Simple Mail Transfer Protocol-based servers such as Microsoft Exchange and Lotus Domino.

Tumbleweed last week began shipping its Messaging Management System (MMS) - Appliance Edition, an e-mail firewall that offers message filtering and management, and includes the company's Dynamic Anti-Spam Service. Tumbleweed is aiming the appliance at midsize organizations.

"Appliances make sense when you have a [single-function] application like e-mail," says Dan Kelson, an analyst for Delphi Group. "If companies have things cobbled together for mail they can consolidate to an appliance and make things less complex."

Such has been the case at Cisco, which runs the C60 and handles a volume of e-mail that can reach 20 million messages per day.

"The appliance concept is strong when dealing with remote sites," says Bailey Szeto, postmaster at Cisco. The appliance is easier to manage than a Sendmail message transfer agent, which requires a server, an operating system and routine patching, he says. Cisco uses Sendmail, the e-mail gateway software that dominates the Internet, on its network, but customizations on the software require a team of three or four people to maintain. Szeto says ease of management made the C60 appliances attractive for remote sites.

For the C60, IronPort has developed Reputation Filter, which is integrated with the company's SenderBase database, a "credit-rating" system that helps determine which of the most prolific senders of e-mail are likely spammers. Working in conjunction with the Brightmail software, Reputation Filter can offer a history of e-mail senders' activity based on their IP addresses and limit the number of messages that senders can deliver through the gateway. The filter also helps in enforcing mail delivery policies. Meanwhile, Brightmail examines the actual messages to determine if they are spam.