With the Zscaler service, companies don't need to maintain their own Web filtering and security software on their servers. Instead, as with many other areas of business software, the filter is based "in the cloud" -- that is, on the Internet.

Enforcing Company Policies

Zscaler said its service "will change the way businesses allow users to access the Internet by providing the right access to the right users, from any place and on any device."

As with a Web proxy, the globally-based infrastructure screens all HTTP traffic incoming and outgoing, looking for malicious software. It can also scan for activity that could run counter to a company's stated policies.

A company's IT department can use Zscaler's network controls to enforce its policies, such as limitations on the kinds of sites, the times when they can be visited, and the kinds of bandwidth-clogging things users might do. Web 2.0 applications, such as social networking , blogging, Webmail and IM, can be identified and managed.

The software-as-a-service approach also addresses what Zscaler said is the insufficient effort many companies have instituted to deal with user-initiated traffic, as well as the coverage problems offered by on-the-road service and sales people.

The Zscaler service redirects traffic to and from a company to one of its data centers, and Web pages are returned after they have been inspected by the software. The service provides protection against bots, malicious content, phishing and peer-to-peer networks.

Zscaler said its software performs inspections at 40 times the speed of most of its competitors, thus avoiding major delays. The company said each of its gateways can process 250,000 transactions per second, up to 100 times faster than other proxy servers.

'A New Standard'

"We are not taking existing web proxies, sticking them in a data center, and calling it a in-the-cloud service," says CEO Jay Chaudhry. Instead, he said, Zscaler's multi-tenant architecture and global security network are setting "a new standard."

Chaudhry is a veteran of the security industry, having founded and sold several companies. CipherTrust was bought by Secure Computing, AirDefense by Motorola, CoreHarbor by USI/AT&T , and SecureIT by VeriSign.

A hosted filtering service could have an appeal among small and midsize businesses, said Merle Sandler, an analyst with industry research firm IDC. "A lot of small businesses don't do much about security," she said, "although there is a growing awareness of the need."

The Zscaler service is subscription-based and priced at $1 to $5 monthly per user, based on the number of users and provided services.

Sandler pointed out that many such businesses, if they have full-time IT personnel, tend to have generalists and not anyone expert in the fast-changing world of Internet security. But businesses are increasingly looking at hosted services, she said, now that they have high-speed connections.