A Default Static Route is configured on the routers so that they should be able to transfer the traffic to a default route if they do not have an entry in the routing table.

Before sending packets to the other networks, routers check their routing table. The routers drop the packets if they are unable to find a specific route on which they have to send traffic. And when a router does not find the route in its routing table it sends the traffic to a default route, if that default route is configured. So basically, the traffic is sent out of the interface mentioned in default route in the absence of an entry in routing table for the traffic.

The default route is most useful when sending traffic to the public network like internet because it is not possible to have the routing table for the entire internet. Hence, the default route helps the routers to send the packets going out to the internet.

In the local area network, when the destination address is not available in the local network then the data is sent out of default gateway which then routed to the other networks by routers; similarly default route enables to find the destination which is not available in the routing table.

In the below lab, we will create a default route on the router to enable routing between different subnets.

This below network scenario is not common in the real world, we have just created this lab to show how default route can route the traffic without the routing table however we can test the real default route in action if we configure default route on the router which is connected to the internet. In packet tracer lab, we cannot emulate the internet so we are testing the default route in simple network.

Note: we will only create a default route on the router. After that, the router should be able to route traffic. You can ping the router 4 from router 0 to check routing in action.

Command explanation – ip route 0.0.0.0 0.0.0.0 192.168.1.2

In the above command 0.0.0.0 means that any IP address with any subnet mark should be sent out of interface 192.168.1.2 if route is not present in the routing table.

Once we configure the default route, we can see the default route in the routing table with S* symbol while static routes are shown with just S symbol

Before configuring the default route, you will see that gateway of last resort is not set however once the default route is configured, gateway of last resort is the routers interface from which traffic will be sent out.

 

default static route

DOWNLOAD

Lab Tasks

  1. Create a default route on router 0 and 1 to reach network 192.168.3.0/24 and 192.168.4.0/24
  2. Create a default route on router 2 to reach network 192.168.1.0/24
  3. Create a default route on router 3 and 4 to reach network 192.168.1.0/24 and 192.168.2.0/24
  4. Test Routing by pinging router 4 from router 0

Lab Configuration

Task 1

Router 0

Router(config)#ip route 0.0.0.0 0.0.0.0 192.168.1.2

Router 1

Router(config)#ip route 0.0.0.0 0.0.0.0 192.168.2.2

Task 2

Router 2

Router(config)#ip route 0.0.0.0 0.0.0.0 192.168.2.1

Task 3

Router 3

Router(config)#ip route 0.0.0.0 0.0.0.0 192.168.3.1

Router 4

Router(config)#ip route 0.0.0.0 0.0.0.0 192.168.3.1

Task 4

Router 0

Router#ping 192.168.4.2