When creating VPCs and VSwitches, you have to specify the private IP address range for the VPC in the form of a Classless Inter-Domain Routing (CIDR) block. Private IP address range of VPC Use 192.168.0.0/16, 172.16.0.0/12, and 10.0.0.0/8 or their subsets as the private IP address range for your VPC. Note the following when planning the private IP address range of VPC: If you have only one VPC and it does not have to communicate with a local data center, you are free to use any of the preceding IP address ranges or their subnets. If you have multiple VPCs, or you want to build a hybrid cloud composed of one or more VPCs and local data centers, we recommend that you use a subset of these standard IP address ranges as the IP address range for your VPC and make sure that the netmask is no larger than /16. You also need to consider whether the classic network is used when selecting a VPC CIDR block. If you plan to connect ECS instances in a classic network with a VPC, we recommend that you do not use the IP address range 10.0.0.0/8, which is also used by the classic network.