>Yes, using the MAC address only is what I'm looking for. My goal is to set up an application that each night turns on a different group of computers, run the patches and updates, does a virus scan and then shuts the computers off again. I'm not clear how the goal could be accomplished with an IP address, even if I give static IPs to each computer, since the IP address only comes into play when the computer has begun to boot up. I have downloaded a few stand alone applications (non Foxpro) that can do it if I only give it a MAC. I also know there are ways to get the IP address with DNS, but to my way of thinking, that shouldn't be needed, since the computer may not get the same address.

Have you tried using the network prefix address as the IP rather than the computer IP address (assumed address)?

ie if your computers are on the 10.0.0.xxx subnet, use 10.0.0.0

This just determines the subnet the wakeup call is broadcat to.