Connect ECS instances through an internal network-Elastic Compute Service(ECS)-阿里云帮助中心

Use an internal network instead of the Internet to connect ECS instances in the same region, including connections to ApsaraDB RDS, Server Load Balancer (SLB), and OSS.

The solution varies by network type, account, region, and security group. Find the solution that matches your scenario in the following table.

Network type	Account	Region	Security group	Solution
Same Virtual Private Cloud (VPC)	Same or different accounts	Same region	Same security group	Connected by default. Note You can also implement network isolation within the security group. See Use security groups.
			Different security groups	See Security groups for different use cases.
Different VPCs	Same or different accounts	Same region	Different security groups	See Overview of VPC connections.
		Different regions