Step 5: Add a DNAT Rule

Scenarios

After a NAT gateway is created, you can add DNAT rules to allow servers in your 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

Log in to the management console.
Under Network, click NAT Gateway.
On the displayed page, click the name of the NAT gateway for which you want to add the DNAT rule.
On the NAT gateway details page, click the DNAT Rules tab.
Click Add DNAT Rule.
Figure 1 Add DNAT Rule

Set the parameters as prompted. For details, see Table 1.

**Table 1** Parameter description
Parameter	Description
Scenario	Select Direct Connect when 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	Specifies the port type, including All ports and Specific port. All ports: indicates the IP mapping method. This method 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: indicates the port mapping method. The NAT gateway forwards the requests with 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	Specifies the EIP that will be used by the server to provide services accessible from 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.
Outside Port	Specifies the port of the EIP. This parameter is available if you select Specific port for Port Type. The value ranges from 1 to 65535. The value can be a single port number or a port range, for example, 80 or 80-100.
Private IP Address	Specifies 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.
Inside Port	Specifies 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. The value can be a single port number or a port range, for example, 80 or 80-100.
Description	Provides supplementary information about the DNAT rule. The description can contain a maximum of 255 characters.