I have a macbook and some windows clients. The macbook can make and receive calls fine. The windows clients can make calls but not receive. I have both a public and private IP assigned to my elastix/asterisk server. Windows can call the macbook internally when it is configured with a private IP, but can't call the macbook when it's configured with the public. It can still make external calls though. The macbook can never call a windows client internally and call center agent console will not call a windows client either. I've disable the windows xp firewall. No joy. Is this a perimeter router thing? What am I missing?