Security
DDoS Attack
Also known as: Distributed Denial of Service, DDoS
Floods a target with traffic from thousands of compromised machines simultaneously, overwhelming it until it becomes unavailable to legitimate users.
A denial of service (DoS) attack sends so much traffic to a target that it can't handle legitimate requests. A distributed version (DDoS) amplifies this enormously by coordinating attacks from thousands or millions of compromised machines — a botnet — making it nearly impossible to simply block the attacking IP.
Attack types
Volumetric attacks — flood the target with raw bandwidth. Measured in Gbps. A 100Gbps DDoS against a server with a 1Gbps uplink wins trivially. Mitigation requires upstream scrubbing (traffic is routed through a service that filters the attack traffic before it reaches your network).
Protocol attacks — exploit weaknesses in network protocol handling. SYN floods exhaust a server's connection table by sending thousands of incomplete TCP handshake requests. Mitigated by firewalls and modern TCP stacks.
Application-layer attacks — target the web application itself. An HTTP flood sends millions of valid-looking HTTP requests, exhausting server processing capacity rather than bandwidth. Harder to distinguish from legitimate traffic; mitigated by WAFs and rate limiting.
Defense
For organizations running public-facing infrastructure, DDoS mitigation means CDN or DDoS scrubbing services (Cloudflare, AWS Shield, Akamai). Your own hardware can't absorb a large volumetric attack — the defense happens upstream.
For organizations running only cloud services without direct infrastructure exposure, your cloud provider's infrastructure provides substantial inherent protection.