A security group functions similarly to virtual firewalls, and is used to set network access controls for one or more ECS instances. When creating instances, you must select a security group. You can also add security group rules to control outbound and inbound network access for all ECS instances in the security group.

To create a security group, perform the following:

1. Log on to the ECS console.

2. In the left-side navigation pane, click Security Groups.

3. Select a region.

4. Click Create Security Group. In the displayed dialog box, enter the following:

   • Security Group Name
     The length must be 2−128 characters. It can contain uppercase letters, lowercase letters, and Chinese characters. It cannot contain numbers, underscores (_), or hyphens (-).

   • Description
     The length must be 2−256 characters. Do not start with http:// or https://.

   • Network Type
     There are two network types, Classic network and VPC. If you select VPC, you must select a specific VPC. If no VPCs have been created in the current region, you must create one first.

5. Click OK.