Distributed Component Object Model (DCOM) is an application level protocol for object-oriented remote procedure calls useful for distributed, component-based systems of all types. It is useful to OPC in that it allows a client to connect to a server running across a network that uses TCP/IP.
To use DCOM, the following steps must be completed:
Connect two machines on a network with TCP/IP network protocol.
Enable DCOM on both machines (normally DCOM is enabled automatically with the operating system installation).
Set the DCOM security to allow the client to connect to the server application.
Windows includes a utility called dcomcnfg.exe. This utility provides a user interface for setting the necessary DCOM settings in the Windows registry.