Preventing SYN flood DoS attacks (Abstract) An improvement to SYN cookies

In 2006, 100,000 servers were broken down just within 10 minutes [1]. Those were the victims of some Denial-of-Service attacks. This news and knowing that some of those victims were so well-known companies like Hotmail and Amazon, indicate the significance of this kind of threats and attacks. “In a DoS attack, a malicious client (called the attacker) performs operations designed to partially or completely prevent legitimate clients from gaining service form a server (called the victim)” [2]. DoS attacks can be categorized in two main classes: logic attacks and flooding attacks. In flooding attacks, which are discussed in this paper, the resources of the victim server are consumed by sending a big number of requests to it in order to make it unable to provide appropriate services to legitimate clients.