A denial of service (DoS) attack is a type of cyber attack that aims to make a computer, network, or other online service unavailable to its users. DoS attacks work by flooding the target with an overwhelming amount of traffic or requests for data, preventing legitimate users from accessing the service. DoS attacks are typically carried out by multiple computers, called a botnet, which are controlled by the attacker.

DoS attacks can be launched in many different ways, but the most common is a distributed denial of service (DDoS) attack. In a DDoS attack, a large number of computers are used to send traffic or requests to the target. The attacker does not need to control any of the computers in the botnet, as the computers are usually infected with malicious software. This makes it difficult for the target to identify the source of the attack.

DoS attacks can be used to target any type of online service, including websites, networks, and even individual computers. They can cause serious disruption and damage to businesses, governments, and individuals. As a result, organizations should implement security measures to protect their systems from DoS attacks. Common measures include firewalls, intrusion detection systems, and rate limiting.