# Configuring Security Group Rules

#### Scenarios

Similar to firewall, a security group is a logical group used to control network access. You can define access rules for a security group to protect the ECSs that are added to this security group.

- Inbound: Inbound rules allow external network traffic to be sent to the ECSs in the security group.
- Outbound: Outbound rules allow network traffic from the ECSs in the security group to be sent out of the security group.

For details about the default security group rules, see Virtual Private Cloud User Guide. For details about configuration examples for security group rules, see Security Group Configuration Examples.

#### Procedure

1. Log in to the management console.
2. Click in the upper left corner and select your region and project.
3. Under Computing, click Elastic Cloud Server.
4. On the Elastic Cloud Server page, click the name of the target ECS.

   The page providing details about the ECS is displayed.

5. Click the Security Groups tab, expand the information of the security group, and view security group rules.
6. Click the security group ID.

   The system automatically switches to the security group details page.

7. On the Inbound Rules tab, click Add Rule. In the displayed dialog box, set required parameters to add an inbound rule.

   You can click + to add more inbound rules.

   Figure 1 Add Inbound Rule

   Table 1 Inbound rule parameter description
   Parameter | Description | Example Value
   --- | --- | ---
   Protocol & Port | Protocol: The network protocol. Currently, the value can be All, TCP, UDP, ICMP, GRE, or others. | TCP
   Port: The port or port range over which the traffic can reach your ECS. The value ranges from 1 to 65535. | 22, or 22-30

   Source

   The source of the security group rule. The value can be a single IP address or a security group to allow access from the IP address or instances in the security group. For example:
   - xxx.xxx.xxx.xxx/32 (IPv4 address)
   - xxx.xxx.xxx.0/24 (IP address range)
   - 0.0.0.0/0 (all IP addresses)
   - sg-abc (security group)

   If the source is a security group, this rule will apply to all instances associated with the selected security group.

   0.0.0.0/0

   Description | Supplementary information about the security group rule. This parameter is optional. The security group rule description can contain a maximum of 255 characters and cannot contain angle brackets (< or >). | N/A

8. On the Outbound Rules tab, click Add Rule. In the displayed dialog box, set required parameters to add an outbound rule.

   You can click + to add more outbound rules.

   Figure 2 Add Outbound Rule

   Table 2 Outbound rule parameter description
   Parameter | Description | Example Value
   --- | --- | ---
   Protocol & Port | Protocol: The network protocol. Currently, the value can be All, TCP, UDP, ICMP, GRE, or others. | TCP
   Port: The port or port range over which the traffic can leave your ECS. The value ranges from 1 to 65535. | 22, or 22-30

   Destination

   The destination of the security group rule. The value can be a single IP address or a security group to allow access to the IP address or instances in the security group. For example:
   - xxx.xxx.xxx.xxx/32 (IPv4 address)
   - xxx.xxx.xxx.0/24 (IP address range)
   - 0.0.0.0/0 (all IP addresses)
   - sg-abc (security group)

   0.0.0.0/0

   Description | Supplementary information about the security group rule. This parameter is optional. The security group rule description can contain a maximum of 255 characters and cannot contain angle brackets (< or >). | N/A

9. Click OK to complete the security rule configuration.

Parent topic: Security Groups