Denial-of-service attack
In computing, a denial-of-service attack (DoS attack) is a cyber-attack in which the perpetrator seeks to make a machine or network resource unavailable to its intended usersby temporarily or indefinitely disrupting services of a hostconnected to a network. Denial of service is typically accomplished by flooding the targeted machine or resource with superfluous requests in an attempt to overload systems and prevent some or all legitimate requests from being fulfilled.[1] The range of attacks varies widely, spanning from inundating a server with millions of requests to slow its performance, overwhelming a server with a substantial amount of invalid data, to submitting requests with an illegitimate IP address.
In a distributed denial-of-service (DDoS) attack, hackers flood a target website with so much traffic from multiple systems that it is rendered inaccessible to legitimate users. A DDoS attack is different than a denial-of-service (Dos) attack, which usually attacks from a single system.
Because DDoS attacks originate from multiple sources and send a larger volume of traffic into the system at once, it is difficult for network administrators to quickly detect and eliminate the threat. As such, DDoS attacks are more damaging than standard DoS attacks as they put an excessive drain on resources and sometimes completely take down an entire network or website.
