Step 3: Add an SNAT Rule

Scenarios

After a NAT gateway is created, add SNAT rules. With an SNAT rule, your servers in a specified subnet can access the Internet by sharing the same EIP.

Each SNAT rule is configured for one subnet or CIDR block. If there are multiple subnets or CIDR blocks in a VPC, you can create several SNAT rules to allow multiple servers to share EIPs.

Prerequisites

A NAT gateway has been created.

Procedure

1. Log in to the management console.
2. Click in the upper left corner and select the desired region and project.
3. Under Network, select NAT Gateway.
4. On the displayed page, click the name of the NAT gateway for which you want to add the SNAT rule.
5. On the SNAT Rules tab, click Add SNAT Rule.
   Figure 1 Add SNAT Rule
   
6. Configure the parameters as prompted. Table 1 describes the parameters.

   Table 1 Parameter descriptions

   Parameter	Condition	Description
   Scenario	N/A	The scenarios where the SNAT rule is used. Select VPC if your servers in a VPC need to access the Internet. Select Direct Connect if the servers that are connected to a VPC through Direct Connect in your data center need to access the Internet.
   CIDR Block	Configure this parameter when you select VPC for Scenario and Custom for CIDR Block. This parameter is available only when you select VPC for Scenario and Custom for CIDR Block. Configure this parameter when you select VPC for Scenario.	In a VPC scenario with CIDR Block as Custom, specify an IPv4 CIDR block, which must be a subset of the VPC subnets. In a VPC scenario with CIDR Block as Existing, specify a VPC subnet in which servers can access the Internet through the SNAT rule. In a Direct Connect scenario, specify a CIDR block of your data center to enable your on-premises servers to access the Internet through the SNAT rule.
   EIP	N/A	The EIP used for accessing the Internet. You can select an EIP that either is not bound to any resource, has been bound to a DNAT rule with Port Type set to Specific port of the current NAT gateway, or has been bound to an SNAT rule of the current NAT gateway. You can select multiple EIPs at once. Up to 20 EIPs can be selected for each SNAT rule. If you have selected multiple EIPs for an SNAT rule, one EIP will be chosen randomly.
   Description	N/A	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 NAT gateway to suite your service requirements.