Appreciate your response. Can you help me how I can find the answers to your questions? The modem and router are supplied by my ISP - Optonline - which as I undersatnd, sets the IP address dynamicly. IP addresses of the devices are not seen outside the network. Thats about as much as I understabd. Can you help me answer your questions. What am I pinging?. and when? Do I ping the desktop from another PC and use the internal IP? Bill