Denial of Service (DoS) attacks are deliberate efforts to overwhelm a system, server, or network, preventing legitimate users from accessing vital services. These attacks can be categorized into volumetric and protocol types, targeting resources like bandwidth or exploiting weaknesses in network protocols. Network resources, such as servers and websites, are common targets, with flooding and ICMP flood attacks being highly used tactics. The key distinction between a DoS and a Distributed Denial of Service (DDoS) attack is that the latter uses multiple devices to carry out the assault, making it more challenging to mitigate. The impacts of these attacks on businesses, government services, and financial institutions are severe, leading to downtime, loss of revenue, and reputational damage. Despite the potential for significant harm, robust cybersecurity measures, including firewalls, DDoS protection tools, and regular security updates, can help detect, mitigate, and prevent these attacks. Historical incidents, such as the massive 2018 attack on GitHub, highlight the necessity for organizations to enhance their defenses against evolving cyber threats.