Default Route is a route that will match all packets when the packet’s destination IP Address# is not known. It reduces the size of the Routing Table#. Typically, Default Route is used to connect edge Router# to Internet Service Provider’s (ISP)# network.
To define a Default Route in Cisco Internetwork Operating System (IOS)#, use the command ip route and assign two quad zeros# (0.0.0.0) to it with an interface’s IP address or name.