Hi there!
Port Mapping ConfigurationPort mapping indicates that the Intranet server is allowed to be open to the Extranet (for example, the Intranet provides the Extranet with a WWW server or FTP server). Port mapping is used to map the Intranet host IP address and port ID to the Extranet IP address and corresponding port ID so that users from Extranets can access the Intranet server. With port mapping, the users cannot see the Intranet IP address, but they see the Extranet IP address.
Navigation Path1. In the navigation tree on the left, choose
Forward Rules >
Port Mapping Configuration. In the pane on the right, click
New. In the dialog box that is displayed, set the parameters related to port mapping, as shown in
Figure 3-58.
Figure 3-58. Port Mapping Configuration 
2. Click
Apply.
Configuration exampleEnable the packets sent from the WAN side to the ONT whose the destination WAN port number is 2000 to be forwarded to the LAN-side PC whose IP address is 192.168.100.20 and the port number is changed to 3000.

Parameter descriptionTable 3-22 describes the parameters related to port mapping.
Table 3-22. Parameters related to port mapping
[tr]Parameter
Description
[/tr]
Enable Port Mapping
| Indicates whether to enable port mapping.
|
Mapping Name
| Indicates the name of the port mapping rule.
|
WAN Name
| Indicates the name of the WAN interface where port mapping is enabled.
|
Internal Host
| Indicates the IP address of the host to which the port is mapped.
|
Protocol
| Indicates the protocol type of port mapping packet, which may be TCP, UDP, or TCP/UDP.
|
Start External Port
| Indicates the destination start port of the external data packet.
|
End External Port
| Indicates the destination end port of the external data packet.
|
Start Internal Port
| Indicates the internal destination start port of the port mapping packet.
|
End Internal Port
| Indicates the internal destination end port of the port mapping packet.
|
Start External Source Port
| Indicates the source start port of the external data packet.
|
End External Source Port
| Indicates the source end port of the external data packet.
|
External Source IP Address
| Indicates the source IP address of the external data packet.
|