OSPF into BGP Route Filtering

Simrid · April 2016

Hi all,

The other day I came across an issue when labbing whereby I couldn't filter my OSPF learnt routes which were being redistrubted into my BGP network.

My question is: To filter redistributed routes for scenarios such as the above, do I need to apply the route map on the OSPF instance or the BGP instance? I guess is would make sense on the OSPF instance?

If that is the case, that's where I was going wrong!

Cheers,
Simon

hurricane1091 · April 2016

Simrid wrote: »

Hi all,

The other day I came across an issue when labbing whereby I couldn't filter my OSPF learnt routes which were being redistrubted into my BGP network.

My question is: To filter redistributed routes for scenarios such as the above, do I need to apply the route map on the OSPF instance or the BGP instance? I guess is would make sense on the OSPF instance?

If that is the case, that's where I was going wrong!

Cheers,
Simon

Forgive me if I misunderstand your goal. But if I do understand, and it's to redistribute routes learned via OSPF into BGP but filter out certain routes, do the following. Create an ACL, name it something that makes sense like OSPF-2-BGP-ACL. Permit whatever you want to be redistributed in there, and remember the implicit deny all. Create a route map, match the ACL, and in your BGP instance redistribute the ospf instance and point to that route-map. All OSPF learned routes that you allowed in the ACL will be redistributed into BGP.

Simrid · April 2016

That's bang on what I wanted, thank you! I forgot you can apply a route map in the redistribution command!

Ahh it all makes sense now! Thanks!

Looks like I need more labbing and less theory haha.

hurricane1091 · April 2016

Glad I could help! I'm familiar with the processs from redistribution at our branch LANs into our MPLS environment so it's easy for me to remember!

OSPF into BGP Route Filtering

Comments