ACP-Cloud1 Exam Dumps : ACP Cloud Computing Certification

For Layer-4 SLB using TCP, the health check determines ECS instance availability based on the successful completion of a TCP 3-way handshake. This ensures that the backend server is reachable and can accept connections, which is critical for reliable TCP-based load balancing.

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Different Alibaba Cloud VPCs are completely isolated from each other by default, but they can communicate with each other over the intranet by using different methods, such as Cloud Enterprise Network (CEN), VPN gateways, VPC peering connections, and PrivateLink. These methods allow you to establish secure and reliable connections between VPCs without exposing your network traffic to the internet. References:

Overview of VPC connections - Alibaba Cloud

Cross-VPC peering - Alibaba Cloud

ALIYUN::VPC::VpcPeerConnection - Alibaba Cloud

When the black hole policy is triggered by excessive DDoS traffic, the affected server is temporarily isolated from the network to prevent further damage. During this period, no services are available, meaning the server cannot provide limited-speed services.