If you want to know What exactly is Port Forwarding and when to use it, please go to the link below: What is Port Forwarding? Before Configuring Your Router There are a few things you need to be aware of when you decide on setting up port forwarding.
If you need an open port on your router then you need to create a port forward. Open ports are used to allow a connection in to your home network from the Internet. They are common in gaming, torrenting, and VOIP configurations.