Cisco: How to selective drop packets without using an access-list

The title actually was a request that I encounter during my CCIE RS preparation. Of course, that in the real world, I would go straight forward and implement an access-list do drop selected packets. But since the lab environment is different for the real one, you might get a task like the above one.

Let’s assume that we have a network topology with a central router (R1) that connects 2 routers (R2 and R3), like in a hub and spoke diagram. Communication between R2 and R3 is done through R1. In this environment routing is already functional, implemented by dynamic or static routing (actually doesn’t matter this is not a topic for this presentation) and R2 can reach R3. We will drop all packets from R2 to R3, but telnet related packets (just to do things a little bit more interesting). As I specified before all this has to be achieved without access-list implementation.

Please have a look to this topology, to have a clear picture of the network environment. After you have checked the topology, watch the video presentation below:

How to drop packets with no ACL