Cisco CCNP and CCIE Study Notes

Consider the network shown above. Router R2 is redistributing between the EIGRP and OSPF protocols. Here is the config on router R2

router eigrp 100
 redistribute ospf 100
 network 12.1.1.0 0.0.0.255
 default-metric 1000 10 255 1 1500
 auto-summary
!
router ospf 100
 log-adjacency-changes
 redistribute static subnets
 redistribute eigrp 100 subnets
 network 2.2.2.2 0.0.0.0 area 0
 network 23.1.1.0 0.0.0.255 area 0
!
ip route 4.4.4.4 255.255.255.255 24.1.1.2

Router R4 has a static default route back to router R2. The network admin has configured a static route to 4.4.4.4/32 on R2 and is redistributing that static route into OSPF. His reasoning is that the static route will make it into OSPF and then since OSPF is being redistributed into EIGRP, the route to 4.4.4.4 will also make it into the EIGRP domain and hence router R1 will have a route to 4.4.4.4/32.

With this in mind, he issues "show ip route" on R1 fully expecting a route to 4.4.4.4/32 to be present there.

R1#sh ip route
Codes: C - connected, S - static, R - RIP, M - mobile, B - BGP
       D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area
       N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
       E1 - OSPF external type 1, E2 - OSPF external type 2, E - EGP
       i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2
       ia - IS-IS inter area, * - candidate default, U - per-user static route
       o - ODR, P - periodic downloaded static route

Gateway of last resort is not set

     1.0.0.0/8 is variably subnetted, 2 subnets, 2 masks
C       1.1.1.1/32 is directly connected, Loopback0
D       1.0.0.0/8 is a summary, 1d22h, Null0
     2.0.0.0/32 is subnetted, 1 subnets
D EX    2.2.2.2 [170/2588160] via 12.1.1.2, 1d22h, Ethernet0/0
     3.0.0.0/32 is subnetted, 1 subnets
D EX    3.3.3.3 [170/2588160] via 12.1.1.2, 1d22h, Ethernet0/0
     23.0.0.0/24 is subnetted, 1 subnets
D EX    23.1.1.0 [170/2588160] via 12.1.1.2, 1d22h, Ethernet0/0
     12.0.0.0/8 is variably subnetted, 2 subnets, 2 masks
C       12.1.1.0/24 is directly connected, Ethernet0/0
D       12.0.0.0/8 is a summary, 1d22h, Null0

However, there is no route to 4.4.4.4/32 on R1.

What is the flaw in the network admin's reasoning? What is the reason a route to 4.4.4.4/32 is not being redistributed from the OSPF domain to the EIGRP domain as he expects? How can he get a route to 4.4.4.4/32 to appear in R1's routing table?

Tags: ospf, eigrp, static route, redistribution, ccie, ccnp