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Anti-DDoS:What is Anti-DDoS Proxy?

Last Updated:Dec 09, 2025

Anti-DDoS Proxy is a proxy service that protects your services from large-scale distributed denial-of-service (DDoS) attacks. The service redirects your service traffic to globally distributed scrubbing centers, which filter out malicious attack traffic and forward only legitimate traffic to your origin server. This process ensures the stability and availability of your services during an attack.

How it works

Anti-DDoS Proxy ensures service stability in three steps:

  1. Traffic redirection: All incoming traffic from the Internet is redirected to an Anti-DDoS scrubbing center by modifying the DNS record or by pointing the service IP address to the IP address of the Anti-DDoS instance. For more information, see Traffic redirection methods.

  2. Traffic scrubbing: The Anti-DDoS scrubbing center uses multilayer detection and filtering engines to defend against Layer 3 and Layer 4 volumetric attacks, such as SYN floods and UDP floods. The center also protects against Layer 7 application-layer attacks, such as HTTP floods. Malicious attack traffic is precisely identified and dropped.

  3. Forwarding traffic to the origin server: After the traffic is scrubbed, legitimate traffic is securely and reliably returned to your origin server through port and protocol forwarding.

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Traffic redirection methods

You can use one of the following methods to direct your service traffic to the IP address of the Anti-DDoS instance for scrubbing.

Redirection Method

Description

Use cases

Pros

Cons

DNS resolution

You change the DNS record of your domain name (for example, www.example.com) to the canonical name (CNAME) address provided by Anti-DDoS Proxy.

Services that are accessed through a domain name, such as websites, web applications, and APIs.

Simple to configure and takes effect quickly. This allows for rapid switching during an attack.

Cannot protect against attacks that directly target the origin IP address.

Direct IP pointing

You configure forwarding rules in the Anti-DDoS instance to use the instance's IP address as the service entry point. The traffic is then sent back to the real server IP address. Clients directly access the IP address of the Anti-DDoS instance.

Non-website services that are accessed directly using an IP address, such as games and app backend services.

Directly protects the IP address and hides the origin server.

Switching IP addresses may affect some client connections.

Benefits

  • Quick and easy deployment

    The service supports two connection types: DNS resolution and direct IP pointing. You do not need to install hardware or software, or adjust routing configurations. You can typically complete the setup in minutes, depending on factors such as DNS propagation time. This approach also hides and protects your origin IP address.

  • AI-driven precise protection

    • Network-layer attack prevention: In addition to traditional feature detection, the service uses an IP reputation library and deep packet inspection (DPI) to accurately identify and block various volumetric attacks.

    • Application-layer CC attack protection: An AI engine automatically learns your service model to accurately identify and filter CC attack traffic. The service supports fine-grained protection policies at the URL level, which significantly reduces O&M complexity.

  • Massive global mitigation capacity

    The global protection network of Anti-DDoS Proxy has a total bandwidth of over 20 Tbps, with more than 5 Tbps of mitigation bandwidth outside the Chinese mainland. This capacity effectively defends against various DDoS attacks at the network, transport, and application layers, ensuring a smooth global access experience.

  • Flexible burstable protection

    You can upgrade your protection bandwidth online at any time, and the changes take effect in seconds. This lets you instantly increase your defense capabilities in response to burst attacks without service interruptions or adjustments.

  • Financial-grade stability and high availability

    The service uses a fully redundant architecture with comprehensive monitoring of data centers, servers, engines, and links. It includes robust automatic failover and recovery mechanisms to ensure 99.95% service availability.

  • Intelligent traffic rerouting

    The service can work with other Alibaba Cloud products to automatically reroute traffic to Anti-DDoS Proxy when an attack occurs. During normal operation, the service does not intervene, which balances cost and security.

Product specifications

Anti-DDoS Proxy is available in two editions based on the physical region of your servers: Anti-DDoS Proxy (Chinese Mainland) and Anti-DDoS Proxy (Outside Chinese Mainland).

Product Type

Instance Edition

Core Features and Differences

Notes

Anti-DDoS Proxy (Chinese Mainland)

Profession

Provides an exclusive IP address, multi-line Border Gateway Protocol (BGP) protection, and supports both basic and burstable protection.

-

Advanced

Provides two advanced mitigation sessions per month (resets monthly).

Contact your account manager to activate this edition.

Anti-DDoS Proxy (Outside Chinese Mainland)

Insurance and Unlimited

  • Both the Insurance and Unlimited mitigation plans are for services deployed exclusively outside China. They differ in billing method, capacity, and the number of advanced mitigation sessions. The Insurance plan offers two per month, while the Unlimited plan has no limit.

  • To reduce latency for users in the Chinese mainland accessing sites outside China, use these plans with a Secure Acceleration (Sec-CMA) line. For more information, see Configure Sec-CMA for Anti-DDoS Proxy (outside the Chinese mainland).

-

Sec-CMA 2.0

Provides access acceleration for users in the Chinese mainland and application-layer DDoS protection. After you select a specific number of DDoS mitigation sessions, it gains the capability to defend against large-volume DDoS attacks from China Telecom, China Unicom, and China Mobile lines.

None

Sec-CMA 2.0 (Insurance) and Sec-CMA 2.0 (Unlimited)

Features are mostly the same as Sec-CMA 2.0. You can disable the Metering Method of 95th Percentile Burstable Clean Bandwidth and 95th Percentile Burstable QPS modes.

The features have been migrated to Sec-CMA 2.0. We do not recommend purchasing new instances. This option is only for existing instances.

Chinese Mainland Acceleration and Sec-CMA 1.0

Legacy versions that do not support China Mobile lines.

We do not recommend purchasing new instances. We recommend that you upgrade to Sec-CMA 2.0. Contact your account manager to activate the upgrade.

Use cases and purchasing recommendations

Server deployment region

User source

Service requirements

Recommended edition

The Chinese mainland

The Chinese mainland and outside the Chinese mainland

General DDoS protection.

Anti-DDoS Proxy (Chinese Mainland) - Profession

Outside the Chinese mainland

Outside the Chinese mainland

Cross-border access acceleration is not required.

Anti-DDoS Proxy (Outside Chinese Mainland) - Insurance or Unlimited

Outside the Chinese mainland

The Chinese mainland

Cross-border access acceleration is required to ensure low latency and stability.

Anti-DDoS Proxy (Outside Chinese Mainland) - Sec-CMA 2.0

Outside the Chinese mainland

The Chinese mainland and outside the Chinese mainland

You need to accelerate cross-border access and serve users from outside the Chinese mainland without migrating your servers.

Combined purchase:

  • Anti-DDoS Proxy (Outside Chinese Mainland) - Sec-CMA 2.0

  • Anti-DDoS Proxy (Outside Chinese Mainland) - Insurance or Unlimited

Outside the Chinese mainland

The Chinese mainland and outside the Chinese mainland

You can migrate your service to different servers based on the user source to enable access across borders. After migration, users from different regions are served by servers and protection editions located in their respective regions.

  • Services for users in the Chinese mainland: Anti-DDoS Proxy (Chinese Mainland) - Profession

  • Services for users outside the Chinese mainland: Anti-DDoS Proxy (Outside Chinese Mainland) - Insurance or Unlimited

Billing

Fees for Anti-DDoS Proxy consist of subscription instance fees and pay-as-you-go burstable fees.