Help Center/ Anti-DDoS Service/ User Guide/ CNAD Basic (Anti-DDoS) User Guide/ Setting a Traffic Scrubbing Threshold to Block Attack Traffic
Updated on 2026-07-15 GMT+08:00

Setting a Traffic Scrubbing Threshold to Block Attack Traffic

Anti-DDoS scrubs traffic when detecting that the incoming traffic of an IP address exceeds the traffic cleaning threshold. It will discard attack traffic and permit normal service traffic.

A threshold that is too high may cause attack traffic to be misidentified as legitimate, leading to false negatives. An overly low threshold may identify peak-hour normal traffic as malicious, causing false positives and service disruption.

Balancing defense precision and service continuity is a critical challenge when mitigating DDoS attacks.

Anti-DDoS provides both default and custom policies, offering threshold configuration in an intelligent and adaptive manner while retaining the flexibility of manual control.

  • Use the default protection policy.

    The initial system policy serves as the default protection policy and applies to all newly purchased EIPs. It does not impact the traffic scrubbing threshold of existing EIPs. The default Traffic Scrubbing Level is 120 Mbit/s and can be modified.

  • Set a protection policy for a specified EIP.

    You can manually set protection policies for your public IP addresses in batches or one by one. The default protection policy will no longer be used for public IP addresses for which protection policies have been manually configured.

If the selected threshold is not suitable for your workloads, some attacks may not be properly mitigated, and service traffic may be mistakenly blocked. Choose a value close to but not greater than your purchased bandwidth.