When the DNS settings are completed, choose "Accept" to exit the window. Then enter the Routing and gateways section for an introduction to gateways.
A router (or gateway) is a machine (or device) that has direct connections to two or more networks. It can exchange information between the networks and route packets from one network to another.
It can do this because it has more than one network card. Each network card has a different address which allows a gateway to be a member of more than one network at the same time.
In private networks a gateway is often used to connect a local, internal network to the Internet.