EIGRP – Advertising a Default Route to Neighbors

In this lab I use five Cisco 7200 routers [IOS 12.4(24)T] to demonstrate how to advertise a default route to neighbors in EIGRP. Below is the network diagram for this lab.

Lab Network Diagram

As you can see R4 is directly connected to the Internet (R5), so we want to advertise to the EIGRP network (R1 – R4) to route all traffic where the destination network is not already in the routing table to route to network 10.10.10.0/30. The “ip default-network 10.0.0.0” command on router R4 will accomplish this as shown below.

R4 - EIGRP configuration for advertising a default route

As I do not have EIGRP running on R5, I do have to add a static route on both R4 and R5. For R4, the command is “ip route 0.0.0.0 0.0.0.0 fastEthernet 1/1” and, for R5, the command is “ip route 172.16.0.0 255.255.0.0 fa 1/0”. Now I can ping 10.10.10.2 from R3 and the routing table on R3 shows the default route advertised by EIGRP.

R3 - ping test and R3 routing table