GRE-tunnels goes down when OSPF is started

[Tero Kaira]

Hello,

I have a small network based GRE-tunnels (IS-IS)

When I add a new network device that should connect to this network using OSPF, the whole network and all GRE-tunnel goes down.

Tunnels and network returns UP again after OSPF is turned from this new network device.

OSPF link between this new device and one of my router should be configured ok and OSPF's Router ID is a router's loopback address.

I closed this loopback interface to see if there is duplicate router-id (=ip address) in use somewhere. There wasn't.

Any ideas how to continue troubleshoot this issue?

[paul driver]

Hello

Not sure I understand this - you haveisis gre tunnels and you then introduce ospf

How are you introducing ospf?

Can you clarify maybe with configuration of a small topology diagram?

res
Paul

[Tero Kaira]

Hello,

I just uploaded a network diagram which contains some configuration lines. So when I start ospf from firewall interface, all my IS-IS network side goes down.

One another question about route maps. Not relating this case.

If I have for example route map LAN1 and one static route configured -> to that nework, and I want it redistribute it for my router is-is side and also for ospf-side, will there be any conflict if there is configured

router isis

redistribute static route-map LAN1

and

router ospf

redistribure static route-map LAN1

BR,

Tero

[Masoud Pourshabanian]

Hello,

How did you configure OSPF? Did you add both subnets of physical interface and Tunnel interface under OSPF configuration? Only subnet of Tunnel must be configured.

Can you share your configuration and topology?

Masoud

[Richard Burts]

When the GRE tunnels go down are there any log messages that might shed light on the issue? (especially any messages about recursive route) One possibility is that in OSPF  you are advertising the tunnel destination in a way that makes it look like the tunnel destination could be reached by going through the tunnel.

I agree with Paul and Masoud that we need a better understanding of the topology of your network and how OSPF was configured to be able to identify the issue better.

HTH

Rick