NGFWs such as those offered by Check Point, Dell SonicWALL, Juniper, Palo Alto Networks and others are extremely high-performance, turnkey appliances intended to stop threats before they reach a computer network and long before the anti-virus software on the individual computer even gets triggered.

FORBES: Next-Generation Firewalls: What Makes Them Next-Gen

It has sued dozens of companies, claiming to have patented the very idea of selling computer software and other electronic goods over a computer network.

ECONOMIST: It was my idea

While McAfee's software may keep viruses from being passed between a handheld computer and corporate network, it doesn't prevent viruses from being delivered wirelessly to the PDA in the first place.

CNN: McAfee aims to shield networks from PDA viruses