The Yoggie Gatekeeper, from Yoggie Security Systems of Netanya, Israel can be thought of as a personal appliance programmed to protect the laptop.

The Yoggie sits inline between the laptop and whatever Internet connection is available. It measures 4 by 2 by 0.8 inches and weighs 2.5 ounces. But the device runs a stack of high-powered security programs, including a firewall and VPN client. Network administrators use the Yoggie Management Server to set up and change security policies, and the Yoggie device enforces them.

To do this, the device has an Intel XScale PXA 260 520GHz processor, with as much as 128MB of memory, and an embedded, hardened operating system based on Linux.

"It's like a bodyguard," says Shlomo Touboul, Yoggie Security Systems founder and CEO, who's launched a number of network management and security companies over the past 20 years. "If [attacker] X tried to reach the laptop [IP] address, the attack actually goes to the Yoggie, with its own IP address, and not to the laptop itself."

Most mobile client security measures require running several security applications and agents on the laptop, making them dependent to varying degrees on the security capabilities of the underlying Windows operating system. As a separate, inline appliance, Yoggie offloads the security software stack from the laptop and sidesteps Windows.

The first version has two 10/100Mbps Ethernet network interface cards.

The Yoggie filters traffic through its security applications. The applications include an open source firewall and the open source Snort program for intrusion detection and prevention.

A separate security analysis program analyzes all these activities to identify new or emerging traffic patterns that show suspicious behavior.

Beta testing is scheduled to start later this month, and the product is expected to ship in November. Yoggie Basic will be priced at US$180 (£96), and provides network and Web security. Yoggie Pro, priced at $220 (£118), has a heftier processor, and more memory and adds email security.