A denial-of-service attack (DoS attack) is an attempt to deny service to legitimate users by overwhelming the server(s) and/or networks with a high number of requests. With some servers, a DoS can cause a system crash that may be classified as severe downtime.

When a DoS attack is orchestrated on a web server, the requests can elicit documents, images, videos, error pages, etc., which are intended to consume a high number of server and network resources to create the impression of an "outage."

For additional information about DoS attacks, see:

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