Abstract: Network security has become more important to personal computer users, organizations, and the military. With the advent of the internet, security became a major concern and the history of security allows a better understanding of the emergence of security technology. The internet structure itself allows for many security threats to occur. If the architecture of the internet is modified, it can reduce the possible attacks that can be sent across the network. Knowing the attack methods allows us to emerge with appropriate security. Many businesses secure themselves from the internet by means of firewalls and encryption mechanisms. The businesses create an “intranet” to remain connected to the internet but secured from possible threats. The entire field of network security is vast and in an evolutionary stage. In order to understand the research being performed today, background knowledge of the internet, its vulnerabilities, attack methods through the internet, and security technology is important and therefore they are reviewed.