Introduction to Route-maps


(Rene Molenaar) #1

This topic is to discuss the following lesson:


(Jose Luis C) #2

Hi Rene, great post!

I am looking for a route-map quite difficult to apply to my BGP.

The target is to filter packets with an specific source network and all loopbacks within a specific destination range. I have tried it with a route-map with an ACL for the source network and a prefix-list for the destinations and a set policy to route it to a next-hop pointing to null but it is not allowed…

% prefix-list and access-list can not co-exist in one route-map sequence.

Any idea how can I achieve this?


(Rene Molenaar) #3

Hello Jose Luis,

This will be difficult. You can use a route-map in combination with BGP for inbound or outbound filtering. For example, when you receive routes, you can use a route-map to permit/deny the routes you want to install. When you advertise routes, you can use a route-map to define the routes that you want to advertise to your peer.

When you want to filter traffic based on source and/or destination addresses, you need different tools like access-lists and apply those to interfaces or use something like CBAC/ZBF.

Rene


(Jose Luis C) #4

Hi Rene, Thank you for your response,

My goal is using this router as a filter to avoid a source to reach some remote destinations, but the difficulty here is the fact I only want to filter /32 destinations within a network, let’s say 10.0.0.0/8.

I do not want to filter advertisements as the remote routers or equipments in between could I need them, I just want if my router look to packet with source X.X.X.X / 28 that want to reach Y.Y.Y.Y / 32 and then discard it. tacking into account that this router has not clue about / 32 but about the full network.

Thanks,