Internet security is the practice of protecting and preserving private resources and information on the Internet.
Computer and network security are challenging topics among executives and managers of computer corporations. Even discussing security policies may seem to create a potential liability.
Network Security is the protection of networks and their services from unauthorized modification, destruction, or disclosure, and provision of assurance that the network performs its critical functions correctly and there are no harmful side-effects. Network security includes providing for data integrity.
A firewall is a system or combination of systems that enforces a boundary between two or more networks. Gateway that limits access between networks in accordance with local security policy. The typical firewall is an inexpensive micro-based Unix box kept clean of critical data, with many modems and public network ports on it, but just one carefully watched connection back to the rest of the cluster.