Commercial firms usually install protective programs called firewalls . These ward off common intrusions from Internet snoops, and are pretty good at it. But they are designed to be used on network servers, and cost big bucks. Several personal firewall programs claim to protect a personal computer from intrusion over an Internet connection. A License Key unlocks the program, along with future updates.
Installation is straightforward, and places an icon in the tray.
You can configure BlackICE for four levels of security, from trusting to paranoid . I feel comfortable with the Nervous setting. When an intrusion is suspected, that icon starts to pulsate and change color, pretty effective notification. Clicking on the icon brings up a dialog box which shows a list of suspected Attacks. The tabs at the top of the window also show information about the type of attack, along with a numerical rating of how serious each attack is.