Help Center/ NAT Gateway/ User Guide (ME-Abu Dhabi Region)/ Getting Started/ Using SNAT to Access the Internet/ Step 3: Add an SNAT Rule
Updated on 2022-01-25 GMT+08:00
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Step 3: Add an SNAT Rule

Scenarios

After the NAT gateway is created, you need to 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 make multiple servers share more EIPs.

Prerequisites

A NAT gateway has been created.

Procedure

  1. Log in to the management console.
  2. Under Network, click NAT Gateway.
  3. On the displayed page, click the name of the NAT gateway for which you want to add the SNAT rule.
  4. On the SNAT Rules tab, click Add SNAT Rule.
  5. Set the parameters as prompted. Table 1 describes the parameters.
    Table 1 Parameter description

    Parameter

    Condition

    Description

    Scenario

    N/A

    Select VPC when your servers in a VPC need to use the SNAT rule to access the Internet.

    Servers in the VPC can share one EIP to access the Internet.

    Type

    This parameter is available when you select VPC for Scenario.

    You can set it to Subnet or Custom based on service requirements.

    Select Subnet when all servers in a VPC subnet need to access the Internet through the SNAT rule.

    Select Custom when specific servers in a VPC subnet need to access the Internet through the SNAT rule.

    Subnet

    This parameter is available when you select VPC for Scenario, and Subnet for Type.

    Specifies the subnet in which servers can access the Internet through the SNAT rule.

    CIDR Block

    This parameter is available when you select VPC for Scenario, and Custom for Type.

    Specifies a CIDR block that is a subset of a VPC subnet CIDR block. Servers whose IP addresses in the custom CIDR block can access the Internet through the SNAT rule.

    EIP

    This parameter is available when you select VPC for Scenario.

    Specifies the EIP used for accessing the Internet.

    You can only select an EIP that has not been bound, 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.

    Monitoring

    N/A

    Create alarm rules in Cloud Eye.

    The alarm rules help you monitor your SNAT connections in a timely manner.

    Description

    N/A

    Provides supplementary information about the SNAT rule. The description can contain a maximum of 255 characters.
  6. Click OK.

    You can add multiple SNAT rules for a NAT gateway to suite your service requirements.