I have a client that has an existing Cisco 2811 router. I do not know what the current configuration of this router. However for a project we are building for this client, we will need to place a second wired router on the LAN side of the Cisco router. This wired router will need to have the ability of connecting and creating IPsec tunnels passing through the Cisco 2811 router to other devices on the Internet. The question I have is what changes or things I need to check and set in the Cisco router in order to do this?
Attached is a communications drawing of the proposed setup.