In today’s business environment, acquiring and distributing information is critical for success. Computer networks have strategic value for companies and can improve productivity and provide a competitive advantage to any business.
The distributed networking style of the 1980s has evolved in to the enterprise-wide networking style of the 1990s. An enterprise networking style includes individuals and LANs within individual departments of a company. It also includes suppliers, customers, distributors, and other trading partners communicating with each other using data, voice, and video. Thousands of enterprise networks can link together through the TCP/IP-based Internet community.
Computer network security becomes increasingly important as the number of networks increases and network size expands. As the sharing of resources and information world-wide becomes easier, the ability to protect information and resources against unauthorized use becomes critical.
It is not possible to have a 100% secure network. Information needs to be accessible to be useful. Balancing accessibility and security is always a tradeoff and is a policy decision made by management.
Good security involves careful planning so that unauthorized access is difficult to achieve and easy to detect. Normally, users on a network are free to communicate with all other users on the network. The network channels are accessible to all. However, access to specific remote systems can be controlled by setting different levels of access security. You can equate this to employees being permitted to freely wander the main corridors of a company, but only a few employees being permitted-access to a research laboratory.
Access strategies can range from quite simple to complex; for example, a password could be required to gain access to a system, or complex encryption schemes might be required instead.
Management needs to decide which security measures to use for internal and external use, and for interfaces to other networks. Internal network users are employees plus any others who need access. External network users are other companies or individuals who need to communicate with the internal users. Different levels of security can be assigned
to any user; for example, some external users could have access privileges to your network while others do not.