A Distributed Denial-of-Service (DDoS) attack is a malicious attempt to disrupt the normal traffic of a targeted server, service, or network by overwhelming the target or its surrounding infrastructure with a flood of Internet traffic. These attacks leverage multiple compromised computer systems as sources of attack traffic, often forming a "botnet," to make it difficult to stop the attack by simply blocking a single source. The primary goal is to render the online service unavailable to its legitimate users. DDoS mitigation involves a set of techniques and tools designed to resist or lessen the impact of such an attack, which includes detecting and filtering malicious traffic, absorbing the traffic surge with high-capacity networks (often called "scrubbing centers"), and employing intelligent routing to divert the attack away from the core infrastructure.