Ospf point to point

[damion10]

I recently had a problem with static routes and OSPF. I had static routes placed on a router to forward traffic to a none OSPF enabled one, but I had forgotten to take the OSPF point-to-point statement off the forwarding serial interface.

The packets would go to the serial interface and be passed on the receiving serial interface but the packet wouldn’t be passed on to the LAN side Ethernet of the router without OSPF on it.

Why would that be as I though that traffic for a directly connected network would just be passed on?

[Kevin Dorrell]

If I understand right, you had a default route to another router via a serial link. The other router did not speak OSPF. The other router would not forward the paclets to its local Ethernet.

This sounds very strange to me. There are several things to check, but I don't think it is related to the OSPF:

1. Are you sure the packets are going to the other router? Is your default route still in place, and is it the most specific prefix for the packets you are sending? On your OSPF router, do a show ip route for the target host address.

2. Is the Ethernet actually up on the other router? Can you ping the target host from the other router?

3. Does the other router have a route back to the source you are testing from?

4. Does the target host have a route back to the source you are testing from, or at least a default route?

I don't think it is anything to do with the ip ospf network point-to-point command, especially if one end of the connection is not talking OSPF. You could try removing it and see if it makes any difference. Let us know.

Kevin Dorrell

Luxembourg

[damion10]

Hi,

1) I can ping the wan/ Serial interface and telnet on to the router without OSPF on it.

2) The router has all interfaces up and has a default route to the other router so a all traffic is sent back to the source.

3) the target host was a switch with it's gateway set to the LAN interface.

I removed the IP OSPF network point-to-point and it works?! It's like the router obeys OSPF before static routes and knows about the serial link as that is directly connected. But not about the ethernet interface as there is no OSPF maybe.

[Richard Burts]

I agree with Kevin that this sounds strange. There are a couple of things that you might be able to clarify. Is there any possibility that the Ethernet of the remote router was not up/up? (If the interface is not up/up the router can not forward out that interface.) Is there any possibility that there is a mask mismatch and the router thinks that the address you are trying to reach is not really in the subnet of its interface?

Perhaps you can supply some specifics that would help us understand this better. It would be helpful to have the configuration of the remote router Ethernet, to have the configuration of the static route, and to have the address that you were trying to ping. Probably also helpful to have the OSPF configuration of the router.

It is hard for me to understand how just removing the ospf network point-to-point could affect forwarding of the packet. Is there any possibility that some other change was made (perhaps by someone else)?

HTH

Rick