OSPF Routes not Installed in Routing Table

[inoc_noc]

There is a router with three OSPF neighbors.  Recently, all routes that would use one particular neighbor were removed from the routing table.  The OSPF neighborship stayed up, but the routes were gone.  All the OSPF database info was still there, but the routes were not being installed in the routing table.

There didn't appear to be any network outage, though that particular neighbor is reached through a VPLS.  Is it possible at one point the ARP entry for that neighbor got corrupted or lost, and the routing process didn't think that next hope was reachable, so it rejected those routes from OSPF?  Or something of that nature?  I'm not even sure if the routing process makes sure the next hop is reachable if it is on a directly connected network.

[smitesh kharecha]

Hi,

Router will install only those routes in routing table, whose next-hop is reachable.

Not sure what exactly happened in your case.

Regards,

Smitesh

[Pulkit Nagpal]

Hello,

To add to Smitesh;s comment, I am looking for more explanation, you mean the router has those routes in its ospf database and the same router does not have any of those routes in routing table?

One reason can be a distribute list which might be blocking those routes from being installed in routing table. Do you think any such changes were made recently? I think if you can share the ospf configuration and show outputs for ospf, people here in comunity will be in better position to assist.

Regards,

Pulkit