Networks are necessary for everyone to communicate with each other over long distances. People tend to transfer data to each other instantly over the Internet to save time. Unfortunately, some people misuse it to carry out different types of attacks, also called network attacks, in order to gain profit. According to the United States Department of Defense (nd), a network attack is an act of disrupting, denying, degrading, or destroying data on computers and computer networks, or the computers and networks themselves. There are many types of network attacks, but only 3 common attacks can be found in the book "Seven Deadliest Network Attacks" by Borkin, Kraus and Prowell (2010) and "CompTIA security+ all-in-one exam guide ( Exam SY0-301) third edition” by (Conklin, White, Williams, Davis, & Cothren, 2011). The types of network attacks we will focus on are denial of service attacks, war call attacks, and man-in-the-middle attacks (see Figure 1.1 in Appendix 1). The first type of network attacks is called denial of service (DoS). This is a common network attack because it can be executed easily (Easttom, 2013). According to Convery (2004), DoS attack is an act aimed at intentionally degrading or blocking the resources of another's computer network. Resources can refer to network bandwidth, computing power, or operating system data structures (Patrikakis, Masikos, & Zouraraki, 2004). The common goal of the attacker performing a DoS attack is to suspend and interrupt another host computer, thereby making its network resources unavailable (Borkin, Kraus & Prowell, 2010). This can be achieved by sending massive messages to the target until its resources are overwhelmed, which corresponds to the same scenario as a road traffic jam in reality. In a DoS ...... middle of paper ...... ys during the key exchange process of the two hosts. Normally the data will be transmitted directly from your network to your friend's network. However, since the communication path is intercepted by the attacker, the data will now be transferred first to the attacker's network before being transferred to your friend. As the public keys are still in the attacker's hands, the attacker can now decrypt the data sent by both of you, resulting in the theft of the data or details of the communication between you and your friend (see Figure 2.2 of Annex 2). In conclusion, the types of network attacks that the report focuses on are denial of service attacks, war call attacks, and man-in-the-middle attacks. Although networks are necessary for everyone because they provide many benefits, there are also people who abuse them to commit immoral acts against other innocent users..