A SURVEY OF NETWORK DENIAL OF SERVICE ATTACKS AND COUNTERMEASURES

Denial of Service (DoS) occurs when legitimate users are prevented from getting service from shared resources or services.  When a DoS attack is mounted from large numbes of distributed sources, it is called a Distributed Denial-of-services (DDoS) attack.  Although DoS attacks are just one kind of Internet-based attack, they have been identified as being of the most immediate concern, according to the Internet Service Providers (ISPs) which participated in the Arbor Networks survey in 2008.  There are several reasons for DoS/DDos being a big concern.

The Internet plays a significant role in our daily lives.  DoS attacks are still a big threat to the Internet, moreover, they are getting more distructive daily.  Everybody is a potential victim of a DoS attack.  There is a need for DoS defense mechanisms that are capable of dealing with the aforementioned problems.  In order to build effective defense systems, it is essential to study DoS attacks and countermeasures.  In the paper, I will overview the history of DoS and DDoS attacks and will present some of the contemporary defense mechanisms.