I'm not sure if this is a RouterOS behaviour or an OSPF behaviour in general. We have a smaller sub-area that is behind another sub-area. To make this work we use a virtual-link to two of the closest backbone-routers. This works for all standard routes, except for the default route, that is simply lost at the ABR (R23) between Area2 and Area3 when running this setup. Not using stub or nssa type areas.
- R02 and R03 has areas backbone and Area2 active.
- R23 as areas backbone, Area2 and Area3 active.
- R23 has the default-route (as ext2) in /routing ospf route, but is not installed in the system table.
- No other router in Area3 gets a default-route.
- R23 does range summary for the linknets used in Area3, not loopbacks
- If I disable both backbone and Area3 on R23, then the default-route gets installed as a regular Area2 router.
Is this by design? We would like to keep our 0.0.0.0/0 throughout the network.
Should we convert Area3 to a stub or nssa to make it work?
An backup solution would be to use a VPLS tunnel to connect Area3 with Area0, but I would like to avoid it if I can.