Overview of Network Security
In the past, the term information security was used to describe the physical security measures
used to keep vital government or business information from being accessed by the public and
to protect it against alteration or destruction. These measures included storing valuable
documents in locked filing cabinets or safes and restricting physical access to areas where
those documents were kept. With the proliferation of computers and electronic media, the
old way of accessing data changed. As technology continued to advance, computer systems
were interconnected to form computer networks, allowing systems to share resources,
including data.
The ultimate computer network, which interconnects almost every publicly accessible
computer network, is the Internet. Although the methods of securing data have changed
dramatically, the concept of network security remains the same as that of information
security.
Because computers can warehouse, retrieve, and process tremendous amounts of data, they
are used in nearly every facet of our lives. Computers, networks, and the Internet are integral
parts of many businesses. Our dependence on computers continues to increase as businesses
and individuals become more comfortable with technology and as technology advances
make systems more user-friendly and easier to interconnect.
A single computer system requires automated tools to protect data on that system from users
who have local system access. A computer system that is on a network (a distributed system)
requires that the data on that system be protected not only from local access but also from
unauthorized remote access and from interception or alteration of data during transmission
between systems. Network security is not a single product, process, or policy, but rather a
combination of products and processes that support a defined policy. Network security is the
implementation of security devices, policies, and processes to prevent unauthorized access to
network resources or alteration or destruction of resources or data.