Guardians at the Gate: Firewalls

Abstract

You’ve just learned about antivirus programs—the first of the three tools you have available to protect your computer. But you also learned that antivirus programs aren’t perfect. Many of their imperfections originate with one obvious fact—an antivirus program can only look at files that are already on your computer. Even though they can do a good job of detecting those files and preventing them from running, the file is nevertheless on your system, which poses some risk.