Network security of the data information is the major concern in present scenario. To protect the data from unauthorized user access or loss is there is need of network security. In network security only the network administrative can access the data.

Network security consist of various polices that are followed by network administrator to check whether the network is secure or not .The main reason to provide network security is to protect the information form loss and make it sure that is being deliver to the right destination .to restrict the user to send same message to another user with name of a third person. Network security is involved in organization, enterprises and other types of institutions. Network security has a wide research area it is prime issues .to makeTo make network free from unauthorized user that can access network, many network security policies or methods have been developed, so that so that only the authorized user can make access to the network.in this way keeping data secure.

There are many methods of network security. The most common and simple is assigningan unique name and a corresponding password which is called as one factor authentication .ATM or mobile phones are termed as Two factor authentication. A finger print or retinal scan comes under three-factor authentication.