OSPF configuration

Unanswered Question
Jan 28th, 2009

I have two routers connected by a serial cable. I have configured ospf but it's not working.

this is how I did it/;

conf t

router ospf

network area 0

and on the other router exactly the same but different network number but the same area, my problem here is I cannot see the networks that i am advertising on the on the router and vice versa.

please help what could be a problem here?

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Joseph W. Doherty Wed, 01/28/2009 - 06:12

The two routers need to share a link with OSPF. You write you're using a "different network number" on the other router. If you want to see other routes, those interfaces need to be known to OSPF.

Assuming the shared link is and the first router has another interface such as and the second router, config might look like:

first router:

router ospf

network area 0

network area 0

second router:

router ospf

network area 0

network area 0

mailaglady2 Wed, 01/28/2009 - 06:40

I have tried that but I still cant see these routes on my routing table.. when I do my "sh ip route" I can't see these routes. i can only see the directly connected ones.

netwalkr1 Wed, 01/28/2009 - 09:05

If both serial interfaces are configure in a point-to-point (PPP/HDLC) configuration make sure you have IP connectivity. I know this is basic but, without the configs posted I'm assuming worst case scenario. Once you verified connectivity, use the network statements area 0 if that is the IP subnet of the serial interfaces. You may also want to configure loopback interfaces for the neighbor ID.

See this link for a step-by-step walkthrough.




zartar911 Wed, 01/28/2009 - 09:35

As what Shaun said, first make sure your layer 2 (port & line are up) & 3 (Ping the other IP address) are working.

After verifying that a sample OSPF configuration could be as follows:


router ospf 1

network area 0

network area 0


router ospf 1

network area 0

network area 0

One other thing to check is the ospf network types are the same.


mailaglady2 Thu, 01/29/2009 - 00:56

Thanks it worked, my problem was with the serial.

I had configured like this area 0 instead of area 0.

Thanks good people, you have been a great help.

netwalkr1 Thu, 01/29/2009 - 05:49

Your welcome! Please mark this thread as "solved" and don't forget to rate the responses.


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