Port Forwarding: A Quick Guide

NDI applications that involve creating a connection between two network environments involve the configuration of other network devices. For example, the NDI Bridge application gives you the necessary tools to handle all aspects of video, audio, metadata, control, tally, and more, but there are still some networking configurations to consider. To ensure connection, we need to discuss two common devices on a network – the router and the firewall.

Typically speaking all networks connect to each other by means of a router. The router is the device that receives and sends all network packets that are not relevant to your local subnet – many times referred to as the gateway. Routers blindly pass traffic between two separate networks.

A router typically has two IP addresses: a public/external IP address and a private IP address. If the local traffic is intended to reach the Internet, then the router will automatically “route” the traffic it receives on its private IP address to the public IP address (and vice-versa) so that traffic can easily flow from the Internet to the local network.

A firewall is a device that actively works toward security of your network by monitoring network traffic and attempt to block unauthorized entry into the network from the outside. Most smaller networks typically have perimeter firewalls which control access and secure local networks. For this reason, most perimeter firewalls also have routing capabilities resulting in both router and firewall being the same device.

To preserve a reasonable level of security while allowing outside computers to connect to your system you will need to forward ports on the router. Port forwarding permits a hand-off between external clients (the far end machine) and a local transaction port which you manually specify. The router will pass NDI requests through to the receiving computer without exposing the internal network to the full Internet.

To enable port forwarding, you need three pieces of information:

  • The login information for the router/firewall. Your router’s manual will have this information, which typically involves entering a specific IP address into your web browser's URL field, and perhaps also a password.
  • The specific IP local address of your receiving computer. You can find this address by opening a command prompt in Windows and typing ipconfig (for Linux and MacOS users, open a Terminal and type ifconfig)
  • The port number to be used for the remote connection. For NDI Bridge the default is 5990 (See Figure 1).

Figure 1


Although the steps vary a bit by brand and model, generally you would proceed as follows:

  1. Log into the router, so it shows its control panel in your web browser.
  2. Select the port forwarding page of the router controls. These options may be found in an obscure place, such as the router’s “Applications and Gaming” page (since online gaming often requires port forwarding).
  3. Enter an Application name, if required (this is for your own recognition purposes, so use anything you like eg. NDI Bridge).
  4. Enter the Start and End port values – you can use the same port number in both fields, but it needs to be the same as chosen in the application (see Figure 1).
  5. If possible, select Both for Protocol (or select UDP).

There are countless makes and models of routers – for information on various models, and a great deal of help on port forwarding generally, we can recommend the following site:

Larger and more sophisticated networks may incorporate dedicated internal firewalls or software firewalls to enhance security. Information on exceptions using the Microsoft Windows® Firewall can be found in the Windows Help system. For other firewalls, please contact your network administrator to configure these types of networks for port forwarding.


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