doc-exports/docs/natgw/umn/nat_qs_0018.html

Step 5: Add a DNAT Rule

Scenarios

After a NAT gateway is created, you can 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 of a server. If there are multiple servers, you can create several DNAT rules to make the servers share one or more EIPs.

Prerequisites

A NAT gateway has been created.

Procedure

1. Log in to the management console.
2. Click in the upper left corner and select the desired region and project.
3. Under Network, select NAT Gateway.
4. On the displayed page, click the name of the NAT gateway for which you want to add the DNAT rule.
5. On the NAT gateway details page, click the DNAT Rules tab.
6. Click Add DNAT Rule.
   Figure 1 Add DNAT Rule
   
7. Configure the parameters as prompted. For details, see Table 1.

   Table 1 Parameter descriptions

   Parameter	Description
   Scenario	Select Direct Connect if servers in your data center need to access the Internet. Servers in your data center that connected to a VPC using Direct Connect or VPN can provide services accessible from the Internet through the DNAT rule.
   Port Type	The port type. You can select All ports or Specific port. All ports: This is equivalent to assigning an EIP to a server. Any requests on the EIP will be forwarded by the NAT gateway to your server based on IP address mapping. Specific port: The NAT gateway only forwards requests with a specific protocol and port on the EIP to the corresponding port of the target 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 will be All by default.
   EIP	The EIP that will be used by the server to provide services accessible from the Internet. You can select an EIP that either is not bound to any resource, 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.
   Outside Port	The port of the EIP. This parameter is available if you select Specific port for Port Type. The value ranges from 1 to 65535. You can enter a single port number, for example, 80.
   Private IP Address	The IP address of the server in the local data center or the user's private IP address. With DNAT, a server using this private IP address in your data center that is connected to a VPC through Direct Connect or VPN can provide services accessible from the Internet.
   Instance Type	The type of the instance that will be providing services accessible from on-premises data centers or remote VPCs. Possible values are: Server Virtual IP address Custom
   NIC	The NIC of the server. This parameter is available when you set Instance Type to Server.
   Inside Port	The port of the server that provides services accessible from the Internet through the DNAT rule. This parameter is available if you select Specific port for Port Type. The value ranges from 1 to 65535. You can enter a single port number, for example, 80.
   Description	Supplementary information about the DNAT rule. Enter up to 255 characters. Angle brackets (<>) are not allowed.

8. Click OK.

Parent topic: Allowing On-Premises Servers to Communicate with the Internet