Yep. Jack Bauer uses them all the time. Every movie, TV show, novel, and newspaper article talks about them. Apparently, they exist as some magical device that at one time both renders a “server” impenetrable and throws open secret files to terrorists. Depending on the character in our little drama, there seems to always hide some trick or pathway around this “firewall” thing, and the description usually relies on pseudo-technical jargon to explain it away.