Use Win32_NetworkAdapterConfiguration Class [WMI] to retrieve many attributes of installed network adapters, including MAC address, IP address, service name, gateway, DHCP server and so on.

FoxPro code sample
http://www.news2news.com/vfp/?example=347&ver=wmi

MSDN link
http://msdn.microsoft.com/library/default.asp?url=/library/en-us/wmisdk/wmi/win32_networkadapterconfiguration.asp