打开debug cry is;debug cry ipsec;后可以看到有如下类型的提示

*Oct 26 11:16:51: %7: (33) received packet from 1.1.1.1, (I) MM_SI3_WR3, MM_VERIFY

*Oct 26 11:16:51: %7:   Exchange type : 0x5

*Oct 26 11:16:51: %7: Error: ISAKMP: payload malformed !

*Oct 26 11:16:51: %CRYPTO-4-ISAKMP_BAD_MESSAGE: IKE message from 1.1.1.1 failed its sanity check or is malformed.