Defending your network against a DDoS attack can be a complex process, especially given that there are so many different methods by which attackers can overload systems or networks or otherwise bring everything to a halt – including the productivity of workers who are dependent on their computers and connectivity to get their jobs done. Cisco has prepared a detailed guide to defending against these types of attacks. Take a look at it here:
http://www.cisco.com/web/about/security/intelligence/guide_ddos_defense.html
