Introduction To Nat Networking

It is not unusual for many within computing-related fields to not fully understand P2P many have not heard of it, and it has become a marketing term for cameras that is associated with ease of use. Within a standard home network, the ISP will supply a router that connects to the internet via copper or fibre community and national infrastructure. This router is the conduit through which all home data will travel, in order to receive and send data across the Internet. The router will have a unique IP address assigned to it by the ISP, which public ally identifies it. Therefore, if a web page is requested by a device within the home network, the router can forward this request and the web server sends the data back to the unique router address provided. The first issue you may notice within this example is how does the router make sure the right data is forwarded to the correct local device which requested it. The Network Address Translation (NAT) protocol is used to allow the router to keep track of what each local (publicly unregistered) device has requested from the Internet essentially, a table is built which maps local IP address to requests for external data. Therefore, when data is received from the Internet, the router can query the NAT table for which local device requested it and forward the data appropriately.

As devices often hold multiple simultaneous open or stand-by connections, ports are used to act as tunnels for forward data to hosts and ensure that the data is sent to the correct process running on the device. This process is simplified for web-data (port numbers 80/443) or secure terminal connections (SSH, port number 22), where routers have inbuilt logic for sending this data to devices, and devices come pre-configured with how to handle data coming through these ports. However, for bespoke software the initial operating system s configuration would not be populated with the required ports. However, this typically isn t an issue with bespoke hardware, for example, a WiFi camera will come configured to recognise the port it will receive/send data from. However, if a request comes from across the Internet to the home router from which the WiFi camera is a local device for the camera s video stream, the router will not recognise where to send the request. None of the local devices have requested the data, therefore, the router is unable to track the two-way communication. In order to facilitate the process, users who wish to request data from a local device across the network, they must configure the router to recognise the port being used for communication. Therefore, when a request comes in for video input from the camera, the router understands to send this request to the specified local device and forwards the connection data port forwarding.

The camera, unaware of the configuration process, utilises its inbuilt software to fulfil the request. WiFi/LAN Ethernet cameras can make use of NAT and port forwarding in order to make connections between the local camera, behind the router and NAT, and the external device, anywhere on the Internet. My next post will explain how this is not possible in the same way over 4G, and how recent companies have solved this issue using P2P.