If the machine being configured will serve as a router between networks that are internal to an organization or between an organization's networks and a service provider, follow the procedure given in ``Configuring a router''.
If the machine being configured will serve as a router directly between an organization's networks and the Internet, acting as the gateway for an autonomous system, follow the procedure given in ``Configuring an external router''.
If the machine being configured is a host that will not perform routing, follow the procedure given in ``Configuring a non-routing host''