The first denial of service (DoS) was observed in 1974, when a curious teenage high school student ran a software experiment to deny computer login access to a room full of users. Since then, a small DoS experiment has evolved into a present day cyber monster - a monster that has evolved dramatically. For example, in the last decade, we have observed the creation of DDoS-for-hire websites that provide the capability of DDoS-as-a-Service for technical and non-technical users.