OSPF NEIGHBOURSHIP ISSUE IN 8 ROUTERS.

[sourav6388]

Hi am getting follwoing error logs in my routers,

seems like i am having duplicate router ID in a router,

but these mesages are being reflected from multiple Ge link towards router each for different link.

please help and suggest checking following logs.

%OSPF-4-FLOOD_WAR: Process 100 re-originates LSA ID 172.42.248.17 type-2 adv-rtr 192.168.0.1 in area 0

6w0d: %OSPF-4-DUP_RTRID_AREA: Detected router with duplicate router ID 192.168.0.1 in area 0

6w0d: %OSPF-4-DUP_RTRID_AREA: Detected router with duplicate router ID 192.168.0.1 in area 0

6w0d: %OSPF-4-FLOOD_WAR: Process 100 re-originates LSA ID 172.42.248.33 type-2 adv-rtr 192.168.0.1 in area 0

6w0d: %OSPF-4-DUP_RTRID_AREA: Detected router with duplicate router ID 192.168.0.1 in area 0

6w0d: %OSPF-4-DUP_RTRID_AREA: Detected router with duplicate router ID 192.168.0.1 in area 0

6w0d: %OSPF-4-FLOOD_WAR: Process 100 re-originates LSA ID 172.42.248.33 type-2 adv-rtr 192.168.0.1 in area 0

6w0d: %OSPF-4-DUP_RTRID_AREA: Detected router with duplicate router ID 192.168.0.1 in area 0

6w0d: %OSPF-4-DUP_RTRID_AREA: Detected router with duplicate router ID 192.168.0.1 in area 0

6w0d: %OSPF-4-FLOOD_WAR: Process 100 re-originates LSA ID 172.42.248.45 type-2 adv-rtr 192.168.0.1 in area 0

6w0d: %OSPF-4-DUP_RTRID_AREA: Detected router with duplicate router ID 192.168.0.1 in area 0

#########################

Do my routers with all ip having error have duplicate router id, or this message if reflected from all of them due to only single fault.,

[Giuseppe Larosa]

Hello Sourav,

there is a single fault that is the duplicated router-id. The LSA type 2 are network LSA that describe a multiaccess segment from the point of view of the Designated Router.

They are flooded to all routers in area 0. For this reason all routers see the Flood war

two different routers have the same router-id and are building new version of LSA all the time

6w0d: %OSPF-4-FLOOD_WAR: Process 100 re-originates LSA ID 172.42.248.45 type-2 adv-rtr 192.168.0.1 in area 0

You need to fix the duplicated OSPF RID issue first, Then all the routers will be happy.

OSPF RID has to be unique in all the routing domain

Hope to help

Giuseppe

[sourav6388]

Hi Giuseppe,

i can understand your solution,

but what here is one more problem , which is something done by pur previous IP planner of our team,

in this ospf 100 process, six router are falling into this 100,

but surprisingly two routers have same RID, 192.168.0.1,

and this ip address is neither of loopback ip or any interface ip, and its also not manually congigured on these routers.

what are other options for a router from where it can learn its Router ID, in such a case,

here i am showing cutting from Running config for router,

router ospf 100

log-adjacency-changes

network 10.140.255.0 0.0.0.15 area 0

network 172.42.248.16 0.0.0.3 area 0

network 172.42.248.32 0.0.0.3 area 0

network 172.42.248.44 0.0.0.3 area 0

!

router ospf 200

router-id 172.42.251.49

log-adjacency-changes

network 10.140.242.136 0.0.0.3 area 0

network 172.42.251.0 0.0.0.3 area 0

network 172.42.251.24 0.0.0.3 area 0

!

see there is no router ID defined for OSPF 100 any how.

Please explain how is that possible.

Thanks

Sourav

[cadet alain]

Hi,

set the rid manually then clear the ospf process 100.

Regards.

Alain

[Giuseppe Larosa]

Hello Sourav,

follow Alain's suggestions you have to fix this as soon as possible

conf  t

router ospf 100

router-id x.x.x.x

end

clear ospf process 100

For the future I would recommend the use of loopback addresses on all routers to provide a stable router-id.

Hope to help

Giuseppe

[sourav6388]

Hi,

ok i can understand procedure how to proceed.

but one my question remains unanswered,

we have not any loop back ip on this and also never used this IP (192.168.0.1) for any purpose and

and also show ip route do not have any info for this ip, then how come this ip is getting learned on this router.

i have no clue please suggest how to find out detail about this IP  coming from,.

Sourav

[Giuseppe Larosa]

Hello Sourav,

either the command router-id was used or in the past there was an interface on the router with that IP address, there is no default value for the OSPF router-id if you try to configure OSPF on a router with no valid IP address configured you would see an error message telling that OSPF process failed to start for the lack of a valid RID on the box.

Again, it is really important to fix first. Understanding what happened in the past can be done later

Hope to help

Giuseppe

[sourav6388]

Hello Giuseppe,

Ok we are correcting this on priority.

Thanks for support.