Perry: "Broadband brings new threats"

Those with a high-speed connection use the net far more than those with just a dial-up modem, and very often choose to leave their PC switched on and connected almost all the time.

Unfortunately, the many vulnerabilities in Microsoft Windows software means that some of these computers are not adequately protected against the most prevalent net attacks and the most virulent viruses.

To help these users, Gatelock sits between a PC and the broadband box that connects it to the net.

It regularly updates itself with the latest information about viruses and hack attacks and spots when someone is trying to subvert the PC.

On patrol

Gatelock owners will get a warning when they are being sent a virus or someone is trying to scan their machine for vulnerabilities.

"There are a number of new threats in the broadband arena," said David Perry, public education director for Trend Micro. "It's far more desirable for those promulgating a denial-of-service attack."

In such attacks, PCs dotted around the web bombard a target site with bogus data packets on behalf of an attacker.

The Gatelock also acts as a basic network hub and allows more than one PC to share a broadband net link.

Monthly fee

Although Trend Micro is one of the first to sell such a gadget, Mr Perry said he expected other security firms to launch similar devices soon.

He said Trend Micro would sell the Gatelock directly to surfers but that the company would also team up with service providers to install the device in customers' homes as part of the monthly broadband subscription fee.

No exact price for Gatelock has yet been announced, but Mr Perry said it would probably cost between $100 and $200 (�70-�140).

The gadget works with Windows, Linux and Apple computers.

BBC News Online is reporting daily from the CeBIT fair.