Speaking of connecting to the Internet, how would we configure our simple 3-system LAN so that it connect to systems on the "outside?" Typically, we'd purchase a router of some kind that can connect to both our Ethernet network and a DSL or Cable modem, or a T1 or phone line. This router would be configured with an IP address so that it could communicate with the systems on our LAN. In turn, we would configure every system on our LAN to use this router as its default route, or gateway. What this means is that any network data addressed to a system that isn't on our LAN would be routed to our router, which would take care of forwarding to remote systems outside our LAN. Generally, your distribution's system initialization scripts handle the setting of a default route for you. The command they use to do this probably looks something like this:

 
route add -net default gw 192.168.1.80 netmask 0.0.0.0 metric 1 

In the above route command, the default route is set to 192168.1.80 -- the IP address of the router. To view all the routes configured on your system, you can type route -n. The route with a destination of "0.0.0.0" is the default route.