Dear Scott and Zuki, It seems somebody raise the same question on how to setup Ping Program on VERA before; however, even I follow the instruction tightly, I still cannot make it work. Here is my system configuration [Host 1] ---> [0]IXP1200[1]<---[Host 2] Host 1: IP Addr. 192.168.133.146, MAC addr. 00:E0:29:00:8A:57" Host 2: IP Addr. 192.168.133.147, MAC addr. 00:E0:29:00:8C:AE" I add the following cache entrys to ipmm.c {"192.168.133.146", "192.168.133.147", "DE:F0:12:34:56:78","00:E0:29:00:8C:AE", 0x01}, {"192.168.133.147", "192.168.133.146", "12:34:56:78:9A:BC","00:E0:29:00:8A:57", 0x00}, Then, compile the Libixprouter.a with VRP. Running IPmm application: sgo ipmm.srec and using all the default setting in the released VERA software. When I try to ping Host 2 from Host 1, from the debug message, It seems that the packets was rcved, but the Microengine cache miss always occurs, and no packet is xmted. I have tried it in both Nov. Released Version and new Released version(With small modification on the atoi function calling in control.c, I guess no overall effect ) Wish you could kindly point out what I am missing. Thanks, Best Regards, Qiu Qiang