Hello, friend!
The Internal ports refer to idle virtual service ports on the ONT (HG8145V5).
The external port is the virtual service port of the service device that you want to forward.
According to your question description:
Internal port: indicates the idle virtual service port on the HG8145V5.
External ports: port 8081 and port 9600 of the server
Note that the IP address on the configuration page is the IP address of the server.
This configuration does not support the forwarding of well-known ports.
Port forwarding is a process for external access to internal services. If you access external services through internal services, packets need to pass through the ISP network. Therefore, you need to ensure that the ISP does not filter packets so that the port forwarding configuration takes effect.
For more information about configuring port forwarding, click: How to configure Huawei ONT port mapping
Thanks!