A Practical Method to Counteract Denial of Service Attacks

Denial of service attacks on the Internet has become a pressing issue following a series of attacks during recent times. Recently, several papers [CER00, MVS01,How98] have reported on the prevalence of such attacks on commercial servers and ISP’s and the disruption they cause to services in today’s Internet. A “denial-ofservice” (DoS) [CER00, CER99, DD99, DO99] is an attempt by attackers to prevent access to resources by legitimate users for which they have authorization. In case of DDoS, an attacker compromises several hosts on the Internet. Often, these are weakly secured machines and they are broken into using well-known defects in standard network service programs and common operating systems. These compromised computers are referred to as zombies.

A Practical Method to Counteract Denial of Service Attacks