Help Center/ NAT Gateway/ User Guide (Ankara Region)/ Getting Started/ Allowing a Private Network to Access the Internet Using SNAT/ Step 3: Add an SNAT Rule
Updated on 2024-04-15 GMT+08:00
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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 Service List in the upper left corner. Under Network, select NAT Gateway.

    The Public NAT Gateway page is displayed.

  3. On the displayed page, click the name of the public NAT gateway on which you need to add an SNAT rule.
  4. On the SNAT Rules tab, click Add SNAT Rule.
  5. 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

    The subnet in which servers can use the SNAT rule to access the Internet

    • 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.

    CIDR Block

    The CIDR block is a subset of the NAT gateway's VPC subnets

    Servers whose IP addresses in the CIDR block can use the SNAT rule to access the Internet.

    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.
  6. 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.