Establish a ClassicLink connection

This topic describes how to establish a ClassicLink connection. After you establish a ClassicLink connection, you can connect classic-network ECS instances to the cloud resources deployed in a VPC.

1. Log on to the ECS console.
2. In the left-side navigation pane, choose Instances & Images > Instances.
3. Select the region to which the target ECS instance belongs.
4. On the Instances page, find the target classic-network instance, and then choose More > Network and Security Group > Set classic link in the Actions column.
5. In the Connect to VPC dialog box, select the target VPC, and then click OK.
6. Click Go to the instance security group list and add ClassicLink rules, and then click Add ClassicLink Rule.
   
   
   
7. In the Add ClassicLink Rule dialog box, set the parameters, and then click OK. The following table describes the parameters.

   Configuration	Description
   Classic Security Group	The name of the classic network security group.
   Select VPC Security Group	Select the security group of the VPC.
   Mode	Select one of the following modes: Classic <=> VPC: The connected resources can access each other (recommended). Classic => VPC: Authorize the classic-network ECS instance to access cloud resources in the VPC. Classic <= VPC: Authorize the cloud resources in the VPC to access the classic-network ECS instance.
   Protocol Type	Select the protocol for communication.
   Port range	Select the port for communication. The port must be in the format of xx/xx. For example, if port 80 is used, enter 80/80.
   Priority	Set the priority for the security group rule. A smaller value indicates a higher priority.
   Description	Enter a description for the security group rule.

8. On the ECS instances page, click the Column Filter icon in the upper-right corner, select Connection Status, and then click OK to view the connection status of the ECS instance.