What does it mean when default route is to a network address?

Question

The default route as configured in a Cisco router is as shown below:

Gateway of last resort is 103.0.0.0 to network 0.0.0.0

What I have came across so far is that the gateway of last resort is configured to a specific IP address such as 172.16.2.1. In this case where it is a network address, does the router choose the most specific route with lowest metric as the default route IP address? Does this also mean that the default route may change depending on the destination IP address?

Answer 1

In an EIGRP network, how do you advertise a default route to all the routers?

There are a few ways to advertise a default route to the rest of the network.

1. Create a static route on the border router (of the EIGRP domain) and redistribute it into EIGRP.
2. Create a summary route (0.0.0.0) on the border router.
3. Use the default-network command on the border router to generate a default route.

The 2nd and 3rd techniques will give you the output you've shown.

default-network is a hold over from classful routing and is rarely used anymore.

Cisco has some good explanations here and here.