Note:
Customers onboarded after September 10, 2026 are subject to the following instructions. If you are an existing Anti-DDoS Pro or Anti-DDoS Advanced customer, see historical documentation. What Is Blocking
Tencent Cloud reduces cloud costs through shared infrastructure, and all users share Tencent Cloud's public network egress. When the attack traffic targeting a protected resource exceeds its protection capacity, Tencent Cloud blocks all public network access to that protected object through the carrier's service to prevent the attack from affecting other unaffected users on the cloud platform and to ensure the stability of the entire cloud platform network. This is referred to as blocking.
Note:
Blocking is a service that Tencent Cloud purchases from carriers. The number and frequency of unblocking operations are subject to carrier-side rules, so frequent manual unblocking is not possible.
Conditions for Triggering Blocking
The blocking threshold equals the upper limit of the protection capacity currently in effect for the protected resource. The protection capacity varies by protected resource type and protection level. For specific values, see DDoS Protection Capacity Description. When attack traffic exceeds the protection capacity, blocking is triggered.
Blocking Duration
The blocking duration is 2 hours by default. The actual blocking duration depends on the number of times blocking is triggered and the attack peak, and can be up to 24 hours. After the blocking duration expires, the system automatically unblocks the cloud resources.
The blocking duration is mainly affected by the following factors:
Whether the attack persists: If the attack persists, the blocking duration will be extended, and the blocking duration will be recalculated from the moment of extension.
Whether attacks are frequent: Resources that are frequently attacked are more likely to experience sustained attacks, and the blocking duration will be automatically extended.
Attack traffic volume: For resources attacked by extremely large traffic, the blocking duration will be automatically extended.
Note:
For users who are blocked too frequently, Tencent Cloud reserves the right to extend the blocking duration and lower the blocking threshold.
Impact During Blocking
During the blocking period, the protected resource cannot receive any public network access, including normal business traffic.
How to Prevent Blocking
Increase Protection Capacity: Subscribe to a DDoS Defender plan and bind cloud resources with public network access to a protection instance at the Advanced Protection or Ultimate Protection level. This increases the upper limit of the protection capacity for your cloud resources and reduces the probability of triggering blocking. For details, see Purchase Guide. Monitor Attack Posture: Continuously track the attack trends of cloud resources through attack analysis, and promptly assess whether the protection level needs to be upgraded.
How to Remove Blocking
After subscribing to a DDoS Defender plan, a single Tencent Cloud root account has three self-service unblocking opportunities per day. Once these are used up, you must wait for the system to unblock automatically or for the quota to reset at midnight the next day.