IronPort uses ‘graylist’ to combat spam

IronPort Systems this week introduced its C60 Messaging Gateway appliance that will incorporate Brightmail’s antispam capabilities later this summer.

The C60 is a high-performance gateway the company claims can process up to 500,000 40-kilobyte messages per hour, making it suitable for use in very high-volume messaging applications. The C60 sits in front of a Notes or Exchange server and controls spam and viruses, helps prevent denial-of-service attacks, monitors outgoing and incoming e-mail flows and offers other mail management functions.

A unique feature of the C60 is its “Reputation Filter System,” which allows differing mail throughput policies to be implemented for different senders. For example, these policies will slow mail delivery for less trustworthy senders, while allowing much higher throughput for mail delivery from more trustworthy senders.

The Reputation Filter uses IronPort’s SenderBase as the source of its information on the trustworthiness of senders, and will use the Brightmail database of known spammers. SenderBase is a free service that monitors the equivalent of 10,000 e-mail recipients and identifies e-mail senders by organization, IP address or domain. SenderBase also tracks senders’ e-mail volumes, their inclusion on public blacklists, end user complaints, and other information to create a score for each sender – the worse the score, the lower the reputation.

SenderBase recipients include a wide variety of sources, including ISPs, universities and corporations of varying size.

The C60 represents an interesting approach to the control and management of spam, viruses and other unwanted content entering a company’s e-mail system. Instead of either fully accepting or completely denying access to senders as in a whitelist or blacklist approach, respectively, the C60 allows variability of policy application based upon the past and current activities of senders.

Because an error in a whitelist or blacklist database can prevent desired e-mail from entering the e-mail system, the graylist approach may be useful in reducing the number of false positives generated, since suspicious e-mail is simply slowed down – not blocked – until the sender can prove it is a more trustworthy source of e-mail.

 Pricing for the C60 starts at $25,000.