IntroductionDenial of service (DoS) and distributed DoS (DDoS) attacks are a means of taking control of a computer terminal or network resources to disrupt network communications. 'a host computer with a connection to the Internet. A DDoS is an attack sent by more than two host computers or zombie computers co-opted into a botnet and DoS is an attack by a single host computer. Either attack will flood a computer or online network with incoming messages to overwhelm the targeted system, thereby denying Internet service or communication with authorized users (US-CERT, 2013). DDoS attacks often involve overloading an Internet service by using increased bandwidth on the application layer and causing services to stop by flooding the packet database with application calls (US-CERT, 2013). An attack can also be carried out by resource flooding when one or more attackers consume a target network or computing resources. CPU, hard drive to degrade the communication of the equipment to put it in a state unavailable to legitimate users. This means of resource flooding can be divided into two types: a malformed packet attack or a protocol exploit attack (Keromytis et al., nd). Keep in mind that a DoS or DDoS attack often results in many casualties, both in the unknowing compromised systems and in the target network. both suffer from seriously degraded services. It is important to note that the network server requires a minimum amount of network bandwidth to operate which is often disrupted and denied during DoS or DDoS activity (UMUC, 2013). History documents that the first DoS attack was carried out by a 15-year-old boy, aka "mafia boy." On February 7, 2000, Canadian youth carried out a series of DoS attacks against Amazon.com and eBay.com. Its attacks yielded a large percentage...... middle of paper...... MUC (2013) Interactive Case Study Module 4. Monitoring, Auditing, Intrusion Detection, Intrusion Prevention and Testing CSEC 640.US-CERT (2013) Security Advisory (ST04-015) Understanding Denial of Service Attacks. Retrieved from http://www.us-cert.gov/ncas/tips/ST04-015Zade A, Patil S & Salunke D (2011) A new technique for detecting and preventing distributed denial of service attacks. Advances in computer science and technology. ISSN 0973-6107 Volume 4 Number 2 (2011) pages 221-225. Retrieved from http://www.ripublication.com/acst.htm Wang IEEE Transactions on Parallel and Distributed Systems, vol. 17, no. 7, July 2006. Retrieved from http://www.computer.org.ezproxy.umuc.edu/csdl/trans/td/2006/07/l0619.pdf