Date Added: Dec 2009
Distributed Denial of Service Attacks imposes a major threat to the availability of Internet services. Most of the applications like banking, trade, and e-commerce are dependent on availability of Internet. Defending Internet from these attacks has become the need of the hour. A typical DDoS defense comprises of three modules namely traffic monitoring, traffic analysis and traffic filtering. Based on placement of these modules, DDoS defense can be categorized into centralized DDoS defense and distributed DDoS defense. In centralized defense, all modules are placed on single point. Under severe DDoS attack, centralized defense itself succumbs to high volume of traffic. Hence it is itself vulnerable to DDoS attacks.