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FYI, I am studying for the CCNA and new to this.

The scenerio, 2 routers R1 and R2. R1 Loopback IP as 192.168.0.1 R2 Loopback IP as 192.168.0.2 Using the loopback IP's as the router ID. I provisioned R1 correctly, R2 is the problem. Instead of 192.168.0.2, i put it as 192.168.1.2 then added the router and network statement router ospf 1 network 192.168.0.2 0.0.0.255 area 0

when I do show ip protocols, the router ID is 192.168.1.2 and the IP shows up under IP protocols

I did change the loopback IP to the correct IP of 192.1680.2 did no router ospf 1 and reprovisioned the network statement

The problem is, the old IP is still under the OSPF. How do I get rid of 192.168.1.2 without deleting the router and starting over?

R2#sh ip protocols 

Routing Protocol is "ospf 1"
  Outgoing update filter list for all interfaces is not set 
  Incoming update filter list for all interfaces is not set 
  Router ID 192.168.0.2
  Number of areas in this router is 2. 2 normal 0 stub 0 nssa
  Maximum path: 4
  Routing for Networks:
    10.0.0.0 0.255.255.255 area 0
    192.168.0.0 0.0.0.255 area 0
  Routing Information Sources:  
    Gateway         Distance      Last Update 
    192.168.0.1          110      00:09:37
    192.168.0.2          110      00:10:00
    192.168.1.2          110      00:48:30
  Distance: (default is 110)
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  • Under the OSPF, shut it down and restart it. Commented Sep 20, 2023 at 14:46
  • Tried clear ip ospf process on R1 and R2 Commented Sep 20, 2023 at 14:55
  • Sometimes you need to reboot the router. Commented Sep 20, 2023 at 16:31
  • Did you try shutdown and no shutdown under the OSPF router process? Commented Sep 20, 2023 at 16:53
  • Your output shows the Router ID has reflected the change as 192.168.0.2 --> "Router ID 192.168.0.2" It looks like something is hanging onto the old source of 192.168.1.2 which makes it shows under Routing Information Sources. What does 'show ip ospf neighbors' and the 'show ip ospf database' say? Clearing the OSPF process should have cleared that out though. Show us your OSPF configuration from R1 and R2. Commented Jan 24, 2024 at 18:06

1 Answer 1

Reset to default
1

I know it's a bit old but it might help. This website is a gold archive.

Answer:

Your current Router-ID is correct (192.168.0.2).

The reason you still see 192.168.1.2 under Routing Information Sources is not because the router is using it, it’s because the old Router-ID is still present in the OSPF database as an LSA that hasn’t aged out yet.

OSPF does not immediately remove LSAs that were originated with the previous Router-ID. An LSA can remain in the LSDB for up to 30 minutes unless the OSPF process is completely restarted and new LSAs overwrite the old ones.

To clear the state, restart the OSPF process so it regenerates all LSAs:

router ospf 1
 shutdown
 no shutdown

or:

clear ip ospf process

(Do this only after you’ve corrected the Loopback IP.)

(If you're running the routers in a virtual environment (EVE-NG, GNS3, Packet Tracer), a full reboot sometimes helps too)

Some others resources: OSPF Basics

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  • Linking to your own site requires you to disclose your affiliation in your post, see the help center. Commented Nov 24 at 7:38
  • Didn't know that, I'm sorry, I change it right away!! Commented Nov 25 at 13:28

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