OSPF Interface in DOWN state

[cameron.scott]

Hi,

I've been looking at a problem on a 3640 ethernet interface. The LAN subnet had disappeared from the routing tables throughout the rest of the network and when I looked at the OSPF interface state it was DOWN, although all the serial's were up and advertised ok. The ethernet interface itself was up/up, although there were a high number of historic errors recorded. I was also informed that the end users on the LAN could ping the interface address OK,but I couldn't verify this myself as I was coming into the router over the WAN. I've resolved this by doing an admin 'shut/no shut' on the interface, but am now trying to establish why the OSPF state changed to DOWN in the first place (there are no other routers on the LAN). Has anyone else came across this, and, if so, what were the resolutions?

[drogell]

Did you determine the ospf interface was down by doing a show ip ospf interface. Also was it ever up and if not I would check my configs you might have amismatch in your subnet mask and the inverse mask in your network statement.

hth

Dennis

[cameron.scott]

Thanks Dennis,

Yes, I did determine that it was down by doing 'show ip ospf interface', 'Show interfaces e0/0' had it up/up and the users on the LAN could ping it. The configs are ok, the router has been in service for over a year and working fine, but for some reason this morning the OSPF state changed to down (for this interface only, all the other serials were still being advertised), the result being that the LAN was isolated.

I'll probably need to raise a case but was just wondering if anyone else had ever experienced this on a production router..