D-ward: source-end defense against distributed denial-of-service attacks

Distributed denial-of-service (DDoS) attacks are a grave and challenging problem. Perpetration requires little effort on the attacker's side, since a vast number of insecure machines provides fertile ground for attack zombies, and automated scripts for exploit and attack can easily be downloaded and deployed. On the other hand, prevention of the attack or the response and traceback of perpetrators is extremely difficult due to a large number of...