what is ‘Free Public Wi-Fi,’ and why doesn’t it ever work?

The “Free Public Wi-Fi” network you see in various public places is the result ( of an old Windows XP bug that causes the OS to set up an ad hoc data-sharing network for connected PCs if it can’t connect to a trusted wireless network auto­matically. Windows names the ad hoc setup after its previous Wi-Fi network connection.

 Long ago, after failing to connect to a trusted network named “Free Public Wi-Fi,” a Windows PC created just such an ad hoc entity. Drawn by theword “Free," local laptop users hoping to get online connected to the impotent ad hoc network, and thus began broadcasting (and perpetuating) it themselves.

Connecting to this type of device-to-device ad hoc network rarely poses any immediate danger, but it won’t get you onto the Web, either. And malicious users could spy on the connection and steal valuable information from you.

To ensure that your PC isn’t inadvertently broadcasting an impotent ad hoc network, update it to at least Windows XP with Service Pack 3. If you run Win­dows Vista, 7, or 8, you have nothing to worry about; nevertheless, avoid con­necting to open Wi-Fi networks with names like “Free Public Wi-Fi” or “Default.”