In addition to the Static Routes configured in the Routing Table, we can also configure a default route or gateway of last resort. This is used to define where packets should go to if we haven’t defined any other route for them.
Suppose R1 has another interface, F1/0 with an IP address of 203.0.113.1 and is connected to the internet at large via that interface. We can use the following command to set this up as the default route:
ip route 0.0.0.0 0.0.0.0 203.0.113.1
This then becomes a catch all for any traffic sent to any route that isn’t otherwise defined in the routing table. This works because any other route configured in the routing table will be more specific.