Thursday, September 22, 2011


The networks are computer networks, both public and private, that are used every day to conduct transactions and communications among businesses, government agencies and individuals. The networks are comprised of "nodes", which are "client" terminals (individual user PCs) and one or more "servers" and/or "host" computers. They are linked by communication systems, some of which might be private, such as within a company, and others which might be open to public access. The obvious example of a network system that is open to public access is the Internet, but many private networks also utilize publicly-accessible communications. Today, most companies' host computers can be accessed by their employees whether in their offices over a private communications network, or from their homes or hotel rooms while on the road through normal telephone lines.
Network security involves all activities that organizations, enterprises, and institutions undertake to protect the value and ongoing usability of assets and the integrity and continuity of operations. An effective network security strategy requires identifying threats and then choosing the most effective set of tools to combat them.
Threats to network security include:
Viruses : Computer programs written by devious programmers and designed to replicate themselves and infect computers when triggered by a specific event
Trojan horse programs : Delivery vehicles for destructive code, which appear to be harmless or useful software programs such as games
Vandals : Software applications or applets that cause destruction
Attacks : Including reconnaissance attacks (information-gathering activities to collect data that is later used to compromise networks); access attacks (which exploit network vulnerabilities in order to gain entry to e-mail, databases, or the corporate network); and denial-of-service attacks (which prevent access to part or all of a computer system)
Data interception : Involves eavesdropping on communications or altering data packets being transmitted
Social engineering : Obtaining confidential network security information through nontechnical means, such as posing as a technical support person and asking for people's passwords
Network security tools include:
Antivirus software packages : These packages counter most virus threats if regularly updated and correctly maintained.
Secure network infrastructure : Switches and routers have hardware and software features that support secure connectivity, perimeter security, intrusion protection, identity services, and security management.
Dedicated network security hardware and software-Tools such as firewalls and intrusion detection systems provide protection for all areas of the network and enable secure connections.
Virtual private networks : These networks provide access control and data encryption between two different computers on a network. This allows remote workers to connect to the network without the risk of a hacker or thief intercepting data.
Identity services : These services help to identify users and control their activities and transactions on the network. Services include passwords, digital certificates, and digital authentication keys.
Encryption : Encryption ensures that messages cannot be intercepted or read by anyone other than the authorized recipient.
Security management : This is the glue that holds together the other building blocks of a strong security solution.
None of these approaches alone will be sufficient to protect a network, but when they are layered together, they can be highly effective in keeping a network safe from attacks and other threats to security. In addition, well-thought-out corporate policies are critical to determine and control access to various parts of the network.

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