OPC operates using the Microsoft Distributed COM (DCOM) architecture. This means that if an OPC Client is connecting to a remote OPC Server, you need to configure DCOM security settings on both the client and server machines.
Note: You need to assign your users sufficient Citect and DCOM security privileges or the OPC Client will not be able to connect to the OPC Server.
The process of configuring DCOM security settings differs depending on which platform you're using: