When DDoS (Distributed Denial of Service) attack traffic exceeds the blocking threshold, several things can happen depending on the security measures and configurations in place:
Traffic Blocking: The primary response is that the excessive traffic is blocked or mitigated to prevent it from overwhelming the targeted system or network. This is often done using specialized DDoS protection services that can identify and filter out malicious traffic.
Rate Limiting: Some systems may implement rate limiting, where the amount of traffic allowed from a single source or IP address is restricted. This helps in preventing a single source from overwhelming the system.
Redirecting Traffic: In some cases, the traffic might be redirected to a scrubbing center or a mitigation service where the malicious traffic is filtered out before the clean traffic is allowed to reach the original destination.
Service Degradation: If the attack is severe and the blocking measures are not sufficient, the targeted service might experience degradation or become unavailable to legitimate users. This can lead to loss of productivity, revenue, and reputation damage.
Automatic Scaling: Some cloud-based services offer automatic scaling capabilities that can increase the capacity of the network or servers to handle the increased load, albeit this is more of a mitigation strategy for legitimate traffic spikes rather than a direct defense against DDoS attacks.
Example: An e-commerce website experiences a sudden surge in traffic due to a DDoS attack. The website's DDoS protection service detects the abnormal traffic pattern and exceeds its blocking threshold. As a result, the service starts to block the malicious traffic, redirecting it to a mitigation center. Legitimate users might experience slower site speeds or temporary access issues until the attack is fully mitigated.
Recommendation: For effective DDoS protection, especially in the cloud environment, services like Tencent Cloud's Anti-DDoS can be utilized. It offers advanced protection features that can automatically detect and mitigate DDoS attacks, ensuring the availability and security of your applications.