Abstract: In an Internet Based Distributed Control System, communication between one or more Clients and one or more controllers is managed by an Internet Hub. A small, inexpensive Web Server reduces the hardware and software resources required to remotely manage controllers through the Internet. One or more Internet Hubs maintain control of the human-machine interface of the system's controllers, increasing security and reducing system cost. Controllers only accept data packets from authorized Internet Hubs and send regular status update information to those Hubs. If alarms are generated, the system is capable of generating and transmitting human readable messages or alarms via e-mail, fax, SMS, or telephone. Controllers are grouped into Local Control Systems in either Peer-to-Peer networks or Master-Slave configurations.