This article discusses network security for libraries. It indicates that there were only six exploit (security exposure) problems, worldwide, reported to the CERT Coordination Center back in 1988. In that year, the CERT had just been established to provide a clearinghouse for exchanging information about network security problems. By 2003, the number of reported security exposure problems would rise to 137,529. And that's just reported problems. The number of unreported problems is unknown but is estimated to easily be five times the number of those reported. In addition, the variety of the types of security problems has been rising constantly as well. The article addresses three major concerns libraries should have relating to network security plans: (1) Confidentiality: protecting information from unauthorized access; (2) Integrity: protecting information from unauthorized alteration; and (3) Availability: providing access to information as required, when required. Each of these areas is usually addressed in different ways because each is exposed to different types of attack. Other topics discussed include: preparing a plan for comprehensive security; aiming to avoid liability; and a plan for best defense. A list and brief descriptions of useful resources for network security is also included.