Please refer to this link - Overview of ports used by Peplink SD-WAN routers and other Peplink services
No specific port for “Send all traffic to”, since SpeedFusion tunnel is up and running. All internet traffics from remote HD4 will be routed through SpeedFusion tunnel. You may need to check with the customer what is the required ports. Common ports for internet access are UDP 53, TCP 80, and TCP443.