5.5 Static and Default Routing
5.5.3 Configuring default routes
To configure a default route, use the ip route and ip default-network commands. Default routes from one host to another are static routes. To set the gateway of last resort, use the 0.0.0.0/0 address as the destination address.

The ip default-gateway command is used with a router on which IP routing is disabled. This command provides the router with an address to which it can forward packets whose destination IP addresses are not in its address space. The following is an example of default route configuration:

Router(config)#ip route 172.254.50.0 255.255.255.0 172.254.45.1
Router(config)#ip default-network 172.254.50.0
Router(config)#ip route 0.0.0.0 0.0.0.0 172.254.45.1