Redistribute routes on ABR router having Area0 and Area 13

[dhruvbhardwaj]

Rtr1 ----Cost1-----> Rtr2 (Area13)

Rtr1 ----Cost1-----> Rtr3 (Area13)

Rtr2 ----Cost10----> Rtr3 (Area0)

Rtr2 ----Cost10----> Rtr4 (Area0)

If i redistribute static route on Rtr2 then Rtr3 learns best route from Rtr1

If i redistribute static route on Rtr4 then Rtr3 learns best route from Rtr2

why?

[dhruvbhardwaj]

Also I do not think router ID can change the routing table because with same setup where your R2 router ID is 11.0.0.2 and you run the below command on R2 it will will prefer path via R2.

router ospf 10

network 100.0.0.2 0.0.0.0 area 0

[MHM Cisco World]

I dont use 100.0.0.0 (subnet between R2 abd R4) in ospf  in my lab.

And R3 prefer path via R2.

External route have forward address it can zero or non-zero

Here your case since I don't use 100.0.0.0 then the forward address is zero'

So the next-hop for this external is the ASRB which it use advertise router IP list in external prefix IP'

So last check we do

Show ip ospf database external 20.20.20.0 

After you change router-id to be IP interface of link connect R2 to R3

MHM

[dhruvbhardwaj]

thats done and still R3 preferring R1

[MHM Cisco World]

Show ip ospf database external 20.20.20.0  <- share this if yoh can

MHM

[dhruvbhardwaj]

Already shared

R2#show ip protocols
Routing Protocol is "ospf 10"
Outgoing update filter list for all interfaces is not set
Incoming update filter list for all interfaces is not set
Router ID 10.1.23.2
It is an area border and autonomous system boundary router
Redistributing External Routes from,
static, includes subnets in redistribution
Number of areas in this router is 2. 2 normal 0 stub 0 nssa
Maximum path: 4
Routing for Networks:
10.1.21.0 0.0.0.255 area 13
10.1.23.0 0.0.0.255 area 0
Reference bandwidth unit is 100 mbps
Routing Information Sources:
Gateway Distance Last Update
10.1.23.2 110 00:00:44
10.1.23.3 110 00:00:34
Distance: (default is 110)

R3#show ip ospf database external 20.20.20.0

OSPF Router with ID (10.1.23.3) (Process ID 10)

Type-5 AS External Link States

Routing Bit Set on this LSA
LS age: 359
Options: (No TOS-capability, DC)
LS Type: AS External Link
Link State ID: 20.20.20.0 (External Network Number )
Advertising Router: 10.1.23.2
LS Seq Number: 80000001
Checksum: 0x53B
Length: 36
Network Mask: /24
Metric Type: 2 (Larger than any link state path)
TOS: 0
Metric: 20
Forward Address: 0.0.0.0
External Route Tag: 0

R3#show ip route 20.20.20.0
Routing entry for 20.20.20.0/24
Known via "ospf 10", distance 110, metric 20, type extern 2, forward metric 2
Last update from 10.1.13.1 on FastEthernet0/1, 00:06:05 ago
Routing Descriptor Blocks:
* 10.1.13.1, from 10.1.23.2, 00:06:05 ago, via FastEthernet0/1
Route metric is 20, traffic share count is 1

[MHM Cisco World]

Make ospf run capability rfc1587/1583

Then check again 

MHM

[dhruvbhardwaj]

Hello  MHM Cisco World /  Georg Pauwen

Could you please share below command output on R3

show ip ospf border-router

[MHM Cisco World]

only R3 ?

MHM

[paul driver · Accepted solution]

Hello
The reason is the route forward metric between between r3-r2 is (10) which is higher than the route forward metric between r3-r1 (2) due to the ospf interface costing you have applied on the link between r3-r2