The goal of a DDoS (Distributed Denial of Service) attack is to make the target system's services unavailable by flooding it with more traffic than it can handle. The principle of the DDoS cleaning system is to detect and filter traffic from malicious attacks and retain legitimate traffic to ensure that the target system can still operate normally.

　　The following are the basic principles of the DDoS server traffic cleaning system:

　　Traffic monitoring and analysis:

　　The cleaning system monitors network traffic and analyzes the source, destination, protocol and other key information of data packets. This can help the system determine which traffic may be malicious.

　　Traffic filtering and classification:

　　Cleaning systems use a variety of technologies to filter and classify traffic. This may include rule-based filtering, black and white lists, reputation scores, behavioral analytics, and more. Legitimate traffic is marked as trustworthy, while malicious traffic is marked as untrustworthy.

　　Reverse proxy and load balancing:

　　Cleaning systems typically handle traffic through reverse proxies and load balancing. A reverse proxy routes client requests to backend servers, filtering out malicious traffic in the process. Load balancing ensures that traffic is evenly distributed to multiple servers, preventing a single point from being targeted.

　　Black hole routing:

　　When large-scale attack traffic is detected, the cleaning system can guide the attack traffic into the "black hole" through blackhole routing, that is, discarding the traffic without passing it to the target server. This mitigates the impact of the attack on the target server.

　　Detection based on behavioral analysis:

　　Cleaning systems may use behavioral analysis technology to detect abnormal traffic patterns. If the traffic does not match normal behavior, the system may flag it as a potential DDoS attack.

　　Real-time response and automation:

　　Cleaning systems usually have real-time response mechanisms and can quickly adapt to new attacks. Automation is a critical part because attacks can develop and evolve in a short period of time. Automation speeds up system responsiveness.

　　Cloud service support:

　　Some DDoS cleaning systems provide cloud service support, allowing enterprises to route their traffic to the cloud for processing. This approach can increase processing power because cloud service providers typically have larger infrastructure.

　　The effectiveness of a DDoS cleaning system depends on its ability to quickly identify and filter out malicious traffic. This is an evolving field that requires constant updates and improvements to adapt to the emergence of new types of DDoS attacks.