Date Added: Jan 2012
Security is an important issue for all computer networks. Hackers and intruders can create many successful attempts to cause the crash of networks and web services of individual companies. Many methods were developed to ensure the protection of the network infrastructure and communication over internet, such as firewalls, encryption and virtual private networks. This paper presents the difference between hackers and intruders with their main motives and intentions with their way of thinking, planning and performing attacks for their personal gain and as well as others gain.