OSPF and multiple IPs on same interface

[TheCowStir]

I have just started working with OSPF and am having problems with some of the automatic route selection.

The setup:
We use both public and private IP addresses on the same segments for customer traffic (public IPs) and private IPs for device management. The problem is that when two routers have both private and public IPs they form two neighbor adjacencies. This only causes a problem for the default route as because both the public IP and Private IP path are the same cost they load balance across each path (even though it is the same physical path).

Is there a way to only use one IP address per interface for OSPF neighborships?

thanks for any help
Todd

[omega-00]

Seconded, just ran into this problem myself yesterday.

[willywonka]

@TheCowStir

I have just started working with OSPF and am having problems with some of the automatic route selection.

The setup:
We use both public and private IP addresses on the same segments for customer traffic (public IPs) and private IPs for device management. The problem is that when two routers have both private and public IPs they form two neighbor adjacencies. This only causes a problem for the default route as because both the public IP and Private IP path are the same cost they load balance across each path (even though it is the same physical path).

Is there a way to only use one IP address per interface for OSPF neighborships?

thanks for any help
Todd

Hi,
try to configure your area and your network as your public network, then set under /routing ospf redistribute-connected=no, the ospf will redistribuite only the connected routes wich belong at your area.

Stefano.

[TheCowStir]

Thanks for the thought, however I am still looking to have the private network in the routing table.

[omega-00]

Is there perhaps a way to have 2 distinct ospf sessions running?

[mrz]

Run ospf only on one network (public or static) not both. Then two adjacencies will not be formed.

[omega-00]

meta routers will probably also be a suitable solution to this problem as well

[awsmith]

@TheCowStir

I have just started working with OSPF and am having problems with some of the automatic route selection.

The setup:
We use both public and private IP addresses on the same segments for customer traffic (public IPs) and private IPs for device management. The problem is that when two routers have both private and public IPs they form two neighbor adjacencies. This only causes a problem for the default route as because both the public IP and Private IP path are the same cost they load balance across each path (even though it is the same physical path).

Is there a way to only use one IP address per interface for OSPF neighborships?

thanks for any help
Todd

We do the same setup. We only put the public IPs into the area and handle the privates via redistribute-connected (metric-type 1).

Note that this does mean that if you are using stub areas, they would then need to become NSSA’s as they will be announcing AS-external LSA’s.