route redistribution OSPF - > EIGRP

[schmidtjoe]

Hi,

during redistributing the OSPF into the EIGRP, I notice the network 10.45.1.0/24 is injected into EIGRP in form of OSPF.

Since the network 10.45.1.0/24 is showing direct connected in the RIB of R3, why it can be redistributed into EIGRP as OSPF?

As I understand only the route existing in the RIB can be redistributed successfully into the destination protocol.

Spoiler

R3#
R3#show ip route | begin Gateway
Gateway of last resort is not set

10.0.0.0/8 is variably subnetted, 7 subnets, 2 masks
S 10.13.1.0/24 [1/0] via 10.25.1.2
C 10.25.1.0/24 is directly connected, GigabitEthernet0/1
L 10.25.1.1/32 is directly connected, GigabitEthernet0/1
C 10.45.1.0/24 is directly connected, GigabitEthernet0/2
L 10.45.1.1/32 is directly connected, GigabitEthernet0/2
C 10.56.1.0/24 is directly connected, GigabitEthernet0/0
L 10.56.1.2/32 is directly connected, GigabitEthernet0/0
192.168.3.0/32 is subnetted, 1 subnets
C 192.168.3.3 is directly connected, Loopback0

R3#show ip eigrp topology 10.45.1.0/24
EIGRP-IPv4 VR(EIGRP_1) Topology Entry for AS(100)/ID(192.168.3.3) for 10.45.1.0/24
State is Passive, Query origin flag is 1, 1 Successor(s), FD is 1310720
Descriptor Blocks:
0.0.0.0, from Redistributed, Send flag is 0x0
Composite metric is (1310720/0), route is External
Vector metric:
Minimum bandwidth is 1000000 Kbit
Total delay is 10000000 picoseconds
Reliability is 255/255
Load is 1/255
Minimum MTU is 1500
Hop count is 0
Originating router is 192.168.3.3
External data:
AS number of route is 1
External protocol is OSPF, external metric is 0
Administrator tag is 0 (0x00000000)

[MHM Cisco World]

can I see the config of R3?

[schmidtjoe]

R3#show running-config | begin Loopback0
interface Loopback0
ip address 192.168.3.3 255.255.255.255
!
interface GigabitEthernet0/0
ip address 10.56.1.2 255.255.255.0
duplex auto
speed auto
media-type rj45
!
interface GigabitEthernet0/1
ip address 10.25.1.1 255.255.255.0
duplex auto
speed auto
media-type rj45
!
interface GigabitEthernet0/2
ip address 10.45.1.1 255.255.255.0
duplex auto
speed auto
media-type rj45
!
interface GigabitEthernet0/3
no ip address
shutdown
duplex auto
speed auto
media-type rj45
!
!
router eigrp EIGRP_1
!
address-family ipv4 unicast autonomous-system 100
!
topology base
default-metric 1000000 1 255 1 1500
redistribute ospf 1
exit-af-topology
network 10.56.1.0 0.0.0.255
exit-address-family
!
router ospf 1
router-id 192.168.3.3
network 10.45.1.0 0.0.0.255 area 0

[MHM Cisco World]

I dont see any wrong 
you config the interface with OSPF then redistribute OSPF into EIGRP, 
It not appear as OSPF in R3 but it redistribute from OSPF into EIGRP. 
since it appear in OSPF DB then it can redistribute into other Router. 

[MHM Cisco World]

I already run small lab, and same result as you get 
the 10.45.1.0/24 is redistribute from OSPF into EIGRP 
I check the 

show ip eigrp topology 
and I see prefix as redistribute.

[Harold Ritter · Accepted solution]

Hi @MHM Cisco World ,

This is normal behavior. By configuring

network 10.45.1.0 0.0.0.255 area 0

under the ospf process, ospf considers that it owns the interface and will redistribute the subnet configured on that interface even though this subnet appears as a connected route in the RIB.

Regards,

[MHM Cisco World]

My be he confuse, but to be sure I run lab and I see ospf redistribute into eigrp.

I see it in eigrp topology. 

[schmidtjoe]

Hi all,

thank you for your answers. Now I got i. As Harold said, by configuring

network 10.45.1.0 0.0.0.255 area 0

under the ospf process will "send" the interface to OSPF process.

Regards

[MHM Cisco World]

when I see this simple Q I think 
if we redistribute connect and OSPF into EIGRP how we can know which one EIGRP is advertise to other neighbor
and finally I find answer

 external protocol is connected 
 external protocol is OSPF 

hope this note help all read this post.