Help Center/ NAT Gateway/ User Guide/ Public NAT Gateways/ Managing SNAT Rules/ Adding an SNAT Rule
Updated on 2024-12-24 GMT+08:00
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Adding an SNAT Rule

Scenarios

After a public NAT gateway is created, add an SNAT rule, so that servers in a VPC subnet or servers that are connected to a VPC through Direct Connect or Cloud Connect can access the Internet by sharing an EIP.

One SNAT rule takes effect for only one subnet. If there are multiple subnets in a VPC, create multiple SNAT rules to allow servers in them to share EIPs.

Notes and Constraints

  • Only one SNAT rule can be added for each VPC subnet.
  • When you add an SNAT rule in the VPC scenario, the custom CIDR block must be a subset of the NAT gateway's VPC subnets.
  • If an SNAT rule is used in the Direct Connect scenario, the custom CIDR block must be a CIDR block of a Direct Connect connection and cannot overlap with the NAT gateway's VPC subnets.
  • There is no limit on the number of SNAT rules that can be added on a public NAT gateway.

Adding an SNAT Rule

  1. Go to the public NAT gateway list page.
  2. Click in the upper left corner and select the desired region and project.
  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.
    Figure 1 Add SNAT Rule
  5. Configure required parameters. For details, see Table 1.
    Table 1 Descriptions of SNAT rule parameters

    Parameter

    Description

    Scenario

    The scenarios where the SNAT rule is used

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

    Select Direct Connect/Cloud Connect if servers in your on-premises data center or in another VPC need to access the Internet.

    CIDR Block

    In a VPC scenario, specify a VPC subnet to enable servers in that subnet to access the Internet using the SNAT rule.

    In a Direct Connect/Cloud Connect scenario, specify a CIDR block of your data center or your VPC to enable your servers to access the Internet using the SNAT rule.

    Public IP Address Type

    The type of the public IP address used for accessing the Internet

    EIP: You can select an EIP that has not been bound to any resource or has been bound to an SNAT rule in the current VPC.

    Global EIP: You can select an unused global EIP or a global EIP that is in use by an SNAT rule of the current 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.
Parent Topic: Managing SNAT Rules