OSPF into BGP Route Filtering

SimridSimrid Member Posts: 327
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
Network Engineer | London, UK | Currently working on: CCIE Routing & Switching

sriddle.co.uk
uk.linkedin.com/in/simonriddle

Comments

  • hurricane1091hurricane1091 Member Posts: 918 ■■■■□□□□□□
    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.
  • SimridSimrid Member Posts: 327
    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.
    Network Engineer | London, UK | Currently working on: CCIE Routing & Switching

    sriddle.co.uk
    uk.linkedin.com/in/simonriddle
  • hurricane1091hurricane1091 Member Posts: 918 ■■■■□□□□□□
    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!
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