Step 4: Create a Security Group

Scenarios

A security group consists of inbound and outbound rules. You can add security group rules to allow or deny the traffic to reach and leave the instances (such as ECSs) in the security group.

When creating an instance (for example, an ECS), you must associate it with a security group. If no security group has been created yet, a default security group will be created and associated with the instance. You can also create a security group and add inbound and outbound rules to allow specific traffic.

Security Group Templates

Several security group templates are provided for you to create a security group. A security group template has preconfigured inbound and outbound rules. You can select a template based on your service requirements. Table 1 describes the security group templates.

**Table 1** Security group templates
Template	Direction	Protocol/Port/Type	Source/Destination	Description	Application Scenario
General-purpose web server	Inbound	TCP: 22 (IPv4)	0.0.0.0/0	Allows all IPv4 addresses to access ECSs in the security group over port 22 (SSH) for remotely logging in to Linux ECSs.	Remotely log in to ECSs. Use the ping command to test ECS connectivity. ECSs functioning as web servers provide website access services.
		TCP: 3389 (IPv4)	0.0.0.0/0	Allows all IPv4 addresses to access ECSs in the security group over port 3389 (RDP) for remotely logging in to Windows ECSs.
		TCP: 80 (IPv4)	0.0.0.0/0	Allows all IPv4 addresses to access ECSs in the security group over port 80 (HTTP) for visiting websites.
		TCP: 443 (IPv4)	0.0.0.0/0	Allows all IPv4 addresses to access ECSs in the security group over port 443 (HTTPS) for visiting websites.
		ICMP: All (IPv4)	0.0.0.0/0	Allows all IPv4 addresses to access ECSs in the security group over any port for using the ping command to test ECS connectivity.
		All (IPv4) All (IPv6)	sg-xxx	Allows ECSs in the security group to communicate with each other.
	Outbound	All (IPv4) All (IPv6)	0.0.0.0/0 ::/0	Allows access from ECSs in the security group to any IP address over any port.
All ports open	Inbound	All (IPv4) All (IPv6)	sg-xxx	Allows ECSs in the security group to communicate with each other.	Opening all ECS ports in a security group poses security risks.
	Inbound	All (IPv4) All (IPv6)	0.0.0.0/0 ::/0	Allows all IP addresses to access ECSs in the security group over any port.
	Outbound	All (IPv4) All (IPv6)	0.0.0.0/0 ::/0	Allows access from ECSs in the security group to any IP address over any port.
Fast-add rule	Inbound	All (IPv4) All (IPv6)	sg-xxx	Allows ECSs in the security group to communicate with each other.	You can select protocols and ports that the inbound rule will apply to.
	Inbound	Custom port and protocol	0.0.0.0/0	Allows all IP addresses to access ECSs in a security group over specified ports (TCP or ICMP) for different purposes.
	Outbound	All (IPv4) All (IPv6)	0.0.0.0/0 ::/0	Allows access from ECSs in the security group to any IP address over any port.

Procedure

Log in to the management console.
Click in the upper left corner and select the desired region and project.
Click in the upper left corner and choose Network > Virtual Private Cloud.
The Virtual Private Cloud page is displayed.
In the navigation pane on the left, choose Access Control > Security Groups.
The security group list is displayed.
In the upper right corner, click Create Security Group.
The Create Security Group page is displayed.

Configure the parameters as prompted.

Figure 1 Create Security Group

**Table 2** Parameter description
Parameter	Description	Example Value
Name	Mandatory Enter the security group name. The security group name can contain a maximum of 64 characters, which may consist of letters, digits, underscores (_), hyphens (-), and periods (.). The name cannot contain spaces. NOTE: You can change the security group name after a security group is created. It is recommended that you give each security group a different name.	sg-AB
Enterprise Project	Mandatory When creating a security group, you can add the security group to an enabled enterprise project. An enterprise project lets you manage cloud resources and personnel by enterprise project. The default project is default. For details about creating and managing enterprise projects, see the Enterprise Management User Guide.	default
Template	Mandatory Several security group templates are provided for you to create a security group. A security group template has preconfigured inbound and outbound rules. You can select a template based on your service requirements.	General-purpose web server
Description	Optional Supplementary information about the security group. The description can contain a maximum of 255 characters and cannot contain angle brackets (< or >).	-