Introduction to Network A network can be termed as a collection of two or more computers that are connected; computers are connected so that they can easily communicate with each other. This communication includes sharing of resources, sharing of files and documents; it also includes every other kind of electronic communication. Computers can be linked up with each other by using any kind of architecture. The basic idea of networking is to share information, no matter how complex the network is designed. Basically, for developing and establishing a network, four elements are required. These include Protocol, Network Interface Card, Cable and Hub. The protocol is a set of rules which are used to make the communication of all the computers identical so that all the computers can understand each other’s language. Network Interface Cards are required for making the connection of different computers with the network – it also allows them to exchange information. The medium is required to connect all the computers can be a cable, infrared and any other medium. Hardware is required for controlling the traffic over a network. Normally, a hub is used to connect the computers. There can be many different types of networks. The networks are categorized based on many factors. The factors over which the networks can be categorized include the size of a network, the complexity of a network, a distance of a network, security of a network, access of a network and how the computers are connected to each other. The network can be arranged peer to peer i.e., without having any dedicated server, or the network can be a client-server network. [Jelen 2003] Network Security No matter what kind of a network is established, how much complicated it is, and how many computers it contains, the main elements that should be present in every kind of network is the network security. Network security can be defined as any step that is taken by companies and organizations for the protection of their networks and systems. It is good to provide more security to a network. The amount of a security is decided by companies and organizations on their own – through experts. Network security is among one of the most discussed topics. All organizations and businesses are primarily concerned with the security of their networks as if the security is weak then any kind of harm can occur to a company on its secret information which could result in a big loss. A network security is not a very simple topic rather it is a very complex issue and must be handled with great efficiency. Many different activities are performed for providing a security and protection to the assets and valuable information of organizations that are going to implement network security. Nowadays, a proper and strong network security is provided by using many different techniques and devices. Few of these techniques and tools may include: antivirus software, firewalls, Intrusion Detection Systems, Virtual Private Networks, identity services, encryption and security management. For providing a high level of security, most of the time, all these tools and techniques are implemented together using layers that make it difficult to access the network easily. Today, network attacks are very common and information theft tak