DDoS attacks and defense mechanisms: a classification

Denial of service (DoS) attacks are an immense threat to Internet sites and among the hardest security problems in today's Internet. Of particular concern - because of their potential impact - are the distributed denial of service (DDoS) attacks. With little or no advance warning, a DDoS attack can easily exhaust the computing and communication resources of its victim within a short period of time. This work presents the problem of DDoS attacks and develops a classification of DDoS defense systems. Important features of each attack and defense system category are described and advantages and disadvantages of each proposed scheme are outlined. The goal of the paper is to place some order into the existing attack and defense mechanisms so that a better understanding of DDoS attacks can be achieved and more efficient defense mechanisms and techniques can be devised.