Step 3: Add an SNAT Rule

Scenarios

After creating a public NAT gateway, add an SNAT rule to enable your servers in a specific subnet to access the Internet through the same EIP.

One SNAT rule can be configured for only one subnet or CIDR block. If there are multiple subnets or CIDR blocks in a VPC, you can add multiple SNAT rules to allow servers to share EIPs.

Prerequisites

A public NAT gateway is available.

Procedure

Log in to the management console.
Click in the upper left corner and select the desired region and project.
Click Service List in the upper left corner. Under Networking, select NAT Gateway.
The Public NAT Gateway page is displayed.
On the displayed page, click the name of the public NAT gateway on which you need to add an SNAT rule.
On the SNAT Rules tab, click Add SNAT Rule.

Configure required parameters. Table 1 describes the parameters.

**Table 1** Descriptions of SNAT rule parameters
Parameter	Description
Scenario	Select VPC if your servers in a VPC will use the SNAT rule to access the Internet.
Subnet	Existing: Select an existing subnet. Custom: Customize a CIDR block or enter a server IP address. NOTE: The customized CIDR block must be a subset of the VPC subnet CIDR block. You can configure a 32-bit host IP address. The NAT gateway takes effect only for this address.
EIP	The EIP used for accessing the Internet You can select an EIP that either has not been bound, has been bound to a DNAT rule of the current public NAT gateway with Port Type set to Specific port, or has been bound to an SNAT rule of the current public NAT gateway. You can select up to 20 EIPs for an SNAT rule. If you have selected multiple EIPs for an SNAT rule, one EIP will be chosen randomly.
Description	Supplementary information about the SNAT rule Enter up to 255 characters.

Click OK.
- You can add multiple SNAT rules for a public NAT gateway to suite your service requirements.
- Each VPC can be associated with multiple public NAT gateways.
- Only one SNAT rule can be added for each VPC subnet.