Configuring Security Group Rules

Scenarios

A security group is a collection of access control rules for ECSs and RDS instances that have the same security protection requirements and are mutually trusted within a VPC.

This section describes how to create a security group to enable specific IP addresses and ports to access RDS.

First check whether the ECS and RDS instance are in the same security group.

• If they are in the same security group, they can communicate with each other by default. No security group rules need to be configured.
• If they are in different security groups, configure security group rules for them, separately.
  • RDS instance: Configure an inbound rule for the security group with which the RDS instance is associated.
  • ECS: The default security group rule allows all outgoing data packets. In this case, you do not need to configure a security group rule for the ECS. If not all outbound traffic is allowed in the security group, you need to configure an outbound rule for the ECS.

For details about the requirements of security group rules, see "Adding a Security Group Rule" in Virtual Private Cloud User Guide.

Precautions

The default security group rule allows all outgoing data packets. ECSs and RDS instances can access each other if they are in the same security group. After a security group is created, you can configure security group rules to control access from and to the DB instances in the security group.

• By default, you can create a maximum of 100 security groups in your cloud account.
• By default, you can add up to 50 security group rules to a security group.
• One RDS instance can be associated with multiple security groups, and one security group can be associated with multiple RDS instances.
• Too many security group rules will increase the first packet latency. You are advised to create no more than 50 rules for each security group.
• To enable access to an RDS DB instance from resources outside the security group, you need to configure an inbound rule for the security group associated with the RDS DB instance.

The default value of Source is 0.0.0.0/0, indicating that RDS DB instances in the security group can be accessed from any IP address.

Procedure

1. Log in to the management console.
2. Click in the upper left corner and select a region and a project.
3. Click in the upper left corner of the page and choose Database > Relational Database Service.
4. On the Instances page, click the target DB instance to go to the Basic Information page.
5. Configure security group rules.

   In the Connection Information area, click the security group name next to the Security Group field.

6. On the Inbound Rules tab page, click Add Rule. In the displayed dialog box, set required parameters to add an inbound rule.
   To add more inbound rules, click +.

   Table 1 Inbound rule parameter description

   Parameter	Description	Example Value
   Priority	Security group rule priority. Value range: 1 to 100. The default value is 1 and indicates the highest priority. A rule with a smaller value has a higher priority.	1
   Action	Action of the security group rule. A rule with a deny action overrides another with an allow action if the two rules have the same priority.	Allow
   Protocol & Port	Protocol: network protocol. Available options include All, TCP, UDP, ICMP, and GRE.	TCP
   	Port: the port over which the traffic can reach your DB instance. RDS for SQL Server can use the default database port 1433 or any port from the range 2100-9500 (excluding 5355 and 5985). If your instance uses 2017 EE, 2017 SE, or 2017 Web Edition, ports 5050, 5353, and 5986 cannot be specified for it.	1433
   Type	IP address type.	IPv4
   Source	Source address. It can be a single IP address, an IP address group, or a security group to allow access from them to your DB instance. Examples: Single IP address: 192.168.10.10/32 (IPv4 address) IP address segment: 192.168.1.0/24 (IPv4 address segment) All IP addresses: 0.0.0.0/0 (any IPv4 address) Security group: sg-abc IP address group: ipGroup-test	0.0.0.0/0
   Description	Supplementary information about the security group rule. This parameter is optional. The description can contain a maximum of 255 characters and cannot contain angle brackets (<) or (>).	-