Configuring default route forwarding

Configuring default route forwarding 

 6.1.4 

This page will show students how to configure default static routes.
Default routes are used to route packets with destinations that do not match any of the other routes in the routing table. Routers are typically configured with a default route for Internet-bound traffic, since it is often impractical and unnecessary to maintain routes to all networks in the Internet. A default route is actually a special static route that uses this format:

ip route 0.0.0.0 0.0.0.0 [next-hop-address | outgoing interface ]

The 0.0.0.0 mask, when logically ANDed to the destination IP address of the packet to be routed, will always yield the network 0.0.0.0. If the packet does not match a more specific route in the routing table, it will be routed to the 0.0.0.0 network.
Use the following steps to configure default routes:
Step 1 Enter global configuration mode.
Step 2 Type the ip route command with 0.0.0.0 for the prefix and 0.0.0.0 for the mask. The address option for the default route can be either the local router interface that connects to the outside networks or the IP address of the next-hop router.
Step 3 Exit global configuration mode.
Step 4 Use the copy running-config startup-config command to save the active configuration to NVRAM.
On the previous page, static routes were configured on Hoboken to access networks 172.16.1.0 on Sterling and 172.16.5.0 on Waycross. It should now be possible to route packets to both of these networks from Hoboken. However, Sterling and Waycross will not know how to return packets to any network that is not directly connected. A static route could be configured on Sterling and Waycross for each of these destination networks. This would not be a scalable solution on a larger network.
Sterling connects to all networks that are not directly connected through interface Serial 0. Waycross has only one connection to all non-directly connected networks. This is through interface Serial 1. A default route on Sterling and Waycross will be used to route all packets that are destined for networks that are not directly connected.  
In the Lab Activity, students will configure a default static route.
The next page will show students how to verify static route configurations.