Hello,

You can set port forwarding on the WAN Configuration page.

1. 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 inFigure 1.

2. Click Apply.

Port 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 to map the Intranet host IP address and port ID to the Extranet IP address and the corresponding port ID so that users from Extranets can access the Intranet server.

With port mapping, the users cannot see the Intranet IP address. They see the Extranet IP address.

Please refer to the below link:

http://support.huawei.com/hedex/hdx.do?docid=EDOC1100062908&id=service_0127&text=Port Mapping Configuration&lang=en

Check whether your device is provided by an ISP and whether they have restrictions on you.

You can also refer to this links : 

How to configure port mapping on Huawei ONT

How to configure Huawei ONT port mapping

Thanks