Help Center/ NAT Gateway/ User Guide (ME-Abu Dhabi Region)/ Managing SNAT Rules/ Adding an SNAT Rule
Updated on 2022-01-25 GMT+08:00
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Adding an SNAT Rule

Scenarios

After the NAT gateway is created, you need to add SNAT rules. With the SNAT rule, servers in a VPC subnet or servers that are connected to a VPC through Direct Connect or VPN can access the Internet by sharing an EIP.

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

    Figure 1 Add SNAT Rule
  5. Specify the parameters as prompted. For details, see Table 1.
    Table 1 Parameter description

    Parameter

    Condition

    Description

    Scenario

    N/A

    Specifies the scenarios in which the SNAT rule is used.

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

    Select Direct Connect when the servers that are connected to a VPC through Direct Connect or VPN in your data center need 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.

    EIP
    • This parameter is available when you select VPC for Scenario.
    • This parameter is available when you select Direct Connect 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.

    You can select multiple EIPs at a time. A maximum of 20 EIPs can be selected for each SNAT rule. The EIP used for the SNAT rule is randomly chosen from the ones you select when you add the rule.

    CIDR Block
    • This parameter is available when you select VPC for Scenario, and Custom for Type.
    • This parameter is available when you select Direct Connect for Scenario.

    In the VPC scenario, specify a VPC subnet to enable the servers whose IP addresses in that subnet to access the Internet through the SNAT rule.

    In the Direct Connect scenario, specify a CIDR block of your data center to enable your servers to access the Internet through the SNAT rule.

    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 NAT gateway. 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.

Parent topic: Managing SNAT Rules