Linux Firewalls, Third Edition

Routing: Getting a Packet from Here to There

Neither a residential site nor most businesses are likely to run routing protocols such as RIP or OSPF. In these cases, routing tables are set up statically, by hand. There's a hint in there. If you're running a routing protocol such as RIP, chances are that you don't need to be; you could operate a more efficient network without that unnecessary overhead. Typically, most sites have a default gateway device, which is the network that interface packets are sent out on when the destination address's route is unknown. The service provider usually provides a single router address, which is the default Internet gateway for the site's local network.