I have a site to site VPN configured between two routers Cisco 2811, and it has been working for a long time, but now the tunnel is up but line protocol is down. There has been no changes in the configuration of the routers and I have done some troubleshooting but I don't know what is wrong. I send attached the configuration of both of the routers and the results of: debug crypto ipsec and debug crypto isakmp and also the routing table in router C (now I don't have access to router D but I know that the configuration I send is the current running one as someone in place has send it to me).
I would appreciate if someone could help me to solve this problem.
Thanks in advance
