Introduction to network security

Networks are mostly the connection of various Lans and are complicated structure with many interrelated parts. Networks can be either public or private and it consist of various nodes and servers. In today's era network is necessary for all sort of activities and are used to conduct activities like transaction and communication among business group, governments and individual as well. The nature of networks and its communication depends upon the interest of the individual and the organization.

Network security involves all the activities that organisation takes to protect the value and the current 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