What is Distributed denial-of-service?

Distributed denial–of–service (DDoS) attack is an attempt to make a machine or network resource unavailable to users by efforts to interrupt or suspend services of a host connected to the Internet. Distributed denial-of-service attacks are usually sent by two or more people, or bots, and denial-of-service attacks are sent by one person or system. Perpetrators of DoS usually attack typically target sites or services hosted on high-profile web servers such as banks, credit card payment gateways, and even root nameservers. Denial-of-service threats are also common in business, and are sometimes responsible for website attacks. This technique has now seen extensive use in certain games, used by server owners, or disgruntled competitors of gaming companies