I have two routers Cisco 837 and 2651xm. Running a debug ipsec on both routers the 837 gives what looks like thing are good. On the 2651 I get --CRYPTO-4-IKMP_BAD_MESSAGE: IKE message from 63.25X.18X.2XX failed its sanity check or is malformed - I'm not sure what this is since the tunnels show to be up on both routers.