... from dial-up bulletin-board systems, software brought in on floppies from home or other sites, and even software that comes pre-infected from manufacturers are just as common as virus-infected ... watching you and your computers.) Espionage is much more difficult to detect than run-of-the-mill break-ins, however. Information theft need not leave any traces at all, and even intrusions ... the problem. Building Internet Firewalls Elizabeth D. Zwicky, Simon Cooper & D. Brent Chapman Second Edition, June 2000 ISBN: 1-5 659 2-8 7 1-7 , 890 pages Completely...