Gateway of last resort is the default route configured on the router
- Default routes are used to direct packets addressed to networks not explicitly listed in the routing table.
- Default routes are invaluable in topologies where learning all the more specific networks is not desirable, as in case of stub networks, or not feasible due to limited system resources such as memory and processing power.
- You can use any of the following commands to configure the gateway of last resort:
- ip default-gateway a.b.c.d
- ip default-network a.b.c.d
- ip route 0.0.0.0 0.0.0.0 a.b.c.d
- The interface must be up/up for the route to display in the routing table as the default route