That sounds like your answer. Someone correct me if I am wrong, but you should not see anything in your arp cache unless some form of communication is attempted. It would be different if your machines were not able to communicate, but I didn't see that you were having problems communicating between them, so it seems to be working properly. ARP will only occur when needed. (ie..."whoever has this IP address, send me your MAC address...and so there you have a brand spankin' new entry in your arp cache - at least temporarily - so that communication to that host is that much faster...)I have attached a link here that may help you a bit if you have questions. I hope this helps.