Port Forwarding

Port Forwarding is a feature present on many modern routers. In essence, it allows you to map a certain outside port of the router to a specific address and port in the LAN.

This means, for example, that every packet sent to port 9732 on the router from the WAN side is forwarded by the router to 192.168.0.44:1001 on the network:

As you can see, this is a static configuration. This is configured on the router itself -- it is not related to any Tibbo equipment. The diagram above shows the setup itself -- no connection is in progress, but the router knows what to do when it gets data to port 9732.

After properly configuring port forwarding on the router, every time a connection is established to a specific port on the "real" IP address of the router, the data is forwarded to a specific host and port on the LAN. Hence:

This shows the same set-up as above, but with a connection in progress. As you can see, the remote host can actually initiate a connection to the Device Server inside the network, because the router knows what to do with the data. Contrast the above diagram with the diagram on How NAT Applies To Device Servers .

Notes on Setting Up Port Forwarding

In order for port forwarding to work, several conditions must be true: