Step 5: Add a DNAT Rule

Scenarios

After a public NAT gateway is created, add DNAT rules to allow servers in your on-premises data center to provide services accessible from the Internet.

You can configure a DNAT rule for each port on a server. If there are multiple servers, you can create multiple DNAT rules.

Prerequisites

A public NAT gateway is available.

Procedure

1. Log in to the management console.
2. Click in the upper left corner and select the desired region and project.
3. Click Service List in the upper left corner. Under Networking, select NAT Gateway.

   The Public NAT Gateway page is displayed.

4. On the displayed page, click the name of the public NAT gateway on which you need to add a DNAT rule.
5. On the public NAT gateway details page, click the DNAT Rules tab.
6. Click Add DNAT Rule.

7. Configure required parameters. For details, see Table 1.

   Table 1 Descriptions of DNAT rule parameters

   Parameter	Description
   Scenario	Select Direct Connect/Cloud Connect if servers in your on-premises data center or in another VPC need to provide services accessible from the Internet.
   Port Type	The port type All ports: All requests received by the gateway through all ports over any protocol will be forwarded to the private IP address of your server. Specific port: Only requests received from a specified port over a specified protocol will be forwarded to the specified port on the server.
   Protocol	The protocol can be TCP or UDP. This parameter is available if you select Specific port for Port Type. If you select All ports, the value of this parameter is All by default.
   EIP	The EIP of the public NAT gateway 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.
   Outside Port	The port of the EIP used by the NAT gateway for external communication This parameter is only available if you select Specific port for Port Type. Range: 1 to 65535 You can enter a specific port number or a port range, for example, 80 or 80-100.
   Private IP Address	The IP address of the server that processes matching packets where requests will be forwarded to This IP address is used by local servers that are connected to a VPC through Direct Connect or servers in another VPC to provide services accessible from the Internet through DNAT. Configure the port of Private IP Address if you select Specific port for Port Type. This IP address is used by the server to provide services accessible from the Internet through DNAT.
   Inside Port	The port of the server over which the originating requests will be forwarded This parameter is only available if you select Specific port for Port Type. Range: 1 to 65535 You can enter a specific port number or a port range, for example, 80 or 80-100.
   Description	Supplementary information about the DNAT rule Enter up to 255 characters.

8. Click OK.
9. View details in the DNAT rule list.

   If Status is Running, the rule has been added.

After you add a DNAT rule, add rules to the security group associated with the servers to allow inbound or outbound traffic. Otherwise, the DNAT rule does not take effect.