Step 3: Add a DNAT Rule

Scenarios

After a public NAT gateway is created, add DNAT rules to allow servers in your VPC to provide services accessible from the Internet.

You can configure a DNAT rule for each port on a server. If multiple servers need to provide services accessible from the Internet, create multiple DNAT rules.

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 a DNAT rule.
4. On the public NAT gateway details page, click the DNAT Rules tab.
5. Click Add DNAT Rule.

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

   Table 1 Descriptions of DNAT rule parameters

   Parameter	Description
   Scenario	Select VPC if your servers in a VPC need to share an EIP 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 communications 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 in the NAT gateway's VPC and processes matching packets where requests will be forwarded to Configure the port of Private IP Address if you select Specific port for Port Type.
   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	Provides supplementary information about the DNAT rule. Enter up to 255 characters. Angle brackets (<>) are not allowed.

7. Click OK.

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.