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New Member

OSPF Multi Area Prevent Default Gateway propagation to the Backbone area

We have OSPF network Multi Area, each area represent different country.

For each country there is different Default Gateway that redistributed to the OSPF domain.

I need good idea to prevent Default Gateway propagation to the Backbone area from each area.

3 REPLIES
Hall of Fame Super Silver

Re: OSPF Multi Area Prevent Default Gateway propagation to the B

Yossi

I do not know of a good way to prevent propagation of default route to the backbone from areas that have a default route. And I am not clear why you want to do this. Perhaps you can clarify this?

If it is important to prevent propagating the default route then the method that would work would be to have every Border router run 2 OSPF processes. One OSPF process would communicate with the other routers within the non-backbone area and the other OSPF process would communicate with the backbone. You could redistribute routes between the OSPF processes and in the redistribution you could suppress the default route from being advertised to the backbone. This approach is more complex and might have other impact on your network. But it is the way that I can think that would allow you to effectively suppress advertisement of a default route from a non-backbone area into the backbone.

HTH

Rick

New Member

Re: OSPF Multi Area Prevent Default Gateway propagation to the B

Rick ,

I would like to do that because I want to prevent situation that LSA database contain

Default Gateway from other Country

Hall of Fame Super Silver

Re: OSPF Multi Area Prevent Default Gateway propagation to the B

Yossi

If that is sufficiently worth the added complexity then I suggest that you implement my suggestion that every border router run 2 OSPF processes, redistribute routes between the processes, and use distribute list to prevent advertisement of the default route into the backbone.

HTH

Rick

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