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

1. Log in to the management console.
2. Click in the upper left corner and select the desired region and project.
3. In the upper left corner of the page, click to expand the service list and choose Networking > NAT Gateway.

   The Public NAT Gateways page is displayed.

4. On the displayed page, click the name of the public NAT gateway on which you need to add an SNAT rule.
5. On the SNAT Rules tab, click Add SNAT Rule.
   Figure 1 Add SNAT Rule
   
6. 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.
   Monitoring	You can create alarm rules on the Cloud Eye console to monitor your SNAT connections and keep informed of any changes in a timely manner.
   Description	Provides supplementary information about the SNAT rule. Enter up to 255 characters. Angle brackets (<>) are not allowed.

7. Click OK.
   

   • You can add multiple SNAT rules for a public NAT gateway to suite your service requirements.
   • Only one SNAT rule can be added for each VPC subnet.