We have a VPN 3005 concentrator (ver 2.5) that will drop a tunnel due to inactivity. Not unusual until you consider the tunnel can only be re-established with a ping from the remote server...but not with a ping from the concentrator. There's another tunnel to another location that works fine. Both configurations are the same with the exception of the slist settings. In the active session list, the tunnel in question shows "Auth'ing" instead of listing a proper username.