Sorry if the question isn’t related to EIGRP summerization. But it’s, generally speaking, about EIGRP.

I know that we can advertise default routes into an EIGRP domain by any of the following:

1- Static default router and redistributes it under the EIGRP process.
2- Using the IP default-network.

I’ve tried the first option and it worked, everything is alright regardless of the AD of 170! But when I tried the IP default-network command, I reached the following:

R1#sh run

interface Loopback0
ip address 1.1.1.1 255.255.255.0
!
interface Serial0/0
ip address 172.12.123.1 255.255.255.0
encapsulation frame-relay
frame-relay interface-dlci 102
frame-relay interface-dlci 103
!
interface Serial0/1
ip address 10.1.1.1 255.255.255.0
!
router eigrp 1
network 1.1.1.0 0.0.0.255
network 10.1.1.0 0.0.0.255
network 172.12.123.0 0.0.0.255
no auto-summary
!
ip http server
ip classless
ip default-network 10.0.0.0

R1#sh ip route

Gateway of last resort is not set

1.0.0.0/24 is subnetted, 1 subnets
C 1.1.1.0 is directly connected, Loopback0
2.0.0.0/24 is subnetted, 1 subnets
D 2.2.2.0 [90/2297856] via 172.12.123.2, 00:26:41, Serial0/0
3.0.0.0/24 is subnetted, 1 subnets
D 3.3.3.0 [90/2297856] via 172.12.123.3, 00:26:41, Serial0/0
4.0.0.0/24 is subnetted, 1 subnets
D 4.4.4.0 [90/2300416] via 172.12.123.3, 00:26:41, Serial0/0
[90/2300416] via 172.12.123.2, 00:26:41, Serial0/0
5.0.0.0/24 is subnetted, 1 subnets
D 5.5.5.0 [90/2297856] via 10.1.1.5, 00:00:52, Serial0/1
172.12.0.0/24 is subnetted, 2 subnets
D 172.12.34.0 [90/2172416] via 172.12.123.3, 00:26:41, Serial0/0
[90/2172416] via 172.12.123.2, 00:26:41, Serial0/0
C 172.12.123.0 is directly connected, Serial0/0
* 10.0.0.0/24 is subnetted, 1 subnets
C 10.1.1.0 is directly connected, Serial0/1

Notice that there is no “ip route” statement created and also there is no route marked as candidate default!

So what is the problem?

- will I have to adjust the prefix of the network 10.0.0.0/24 at the interface to be /8 for the EIGRP to know about and then use it as a default network? .. I guess not!

- will I have to adjust the network command under the EIGRP to include the /8 prefix network instead of /24 prefix and then EIGRP will now know about the network and use it with ip default-network? .. I guess not!

NOTE: I hope that you can write a post about IGPs and Candidate Default Routes! especially using the ip default-network as they are tend to be confusing.

Thanks in advance.