To answer your first question, the only setting you need to make for port forwarding is in the port forwarding section. This is where you will specify the ports that need to be forwarded and the LAN IP address of the device that should receive the forwarded traffic.
Regarding your second question, if you have already set up the port forwarding rules correctly, then you do not need to create any additional rules in the Traffic Rules section.
In terms of your third question, it is possible to forward traffic from a public IP to a LAN IP. This is a common practice for allowing external access to devices or services hosted within a private network. The diagram you mentioned in the Teltonika Networks website represents a typical network architecture where a private network is connected to the internet through a router with a public IP address assigned by an ISP.
Wireless LTE networks typically use a similar network architecture where the LTE modem serves as the router connecting the private network to the internet through a public IP address assigned by the cellular network provider. However, the specifics of the configuration may vary depending on the wireless provider and the equipment used.
