The Internet is literally a network of networks. It is comprised of ten thousands of interconnected networks spanning the globe. The computers that form the Internet range from huge mainframes in research establishments to modest PCs in people's homes and offices. Despite the recent hype, the Internet is not a new phenomenon. Its roots lie in a collection of computers that were linked together in the 1970s to form the US Department of Defense's communications systems. Fearing the effects of nuclear attack, the government dispersed its information across several computers rather than just one central computer. A set of rules or protocols, kno