How OPCNet Broker replaces DCOM-based OPC Classic connections inside a single plant network with one encrypted tunnel, making OPC links simpler to deploy, secure and troubleshoot.
OPC (Open Platform Communications) Classic remains the backbone of data exchange in many plants, linking PLCs (programmable logic controllers), SCADA (supervisory control and data acquisition) systems, DCS (distributed control system) platforms, historians and plant applications. OPC Classic relies on Microsoft DCOM (Distributed Component Object Model) whenever the OPC client and the OPC server run on different machines.
This use case shows how OPCNet Broker® DA HDA AE removes the need to configure DCOM between machines, even when both systems sit on the same network.
Even inside a single plant network, a remote OPC Classic connection requires DCOM permissions, authentication settings, firewall rules and Windows security policies to be configured and kept aligned on both machines.
These settings are time-consuming to get right, hard to troubleshoot when a connection fails, and easily broken by operating system updates or security hardening. Every DCOM opening is also a potential attack surface that must be managed and reviewed over the life of the system.
The plant needed an approach that would:
OPCNet Broker® establishes a tunnel between the OPCNet Broker Client Side, installed on the OPC client machine, and the OPCNet Broker Server Side, installed on the OPC server machine.
The OPC client connects locally to the OPCNet Broker Client Side as if it were the OPC server. OPC calls are carried through the encrypted tunnel over a single configurable TCP (Transmission Control Protocol) port, and the OPCNet Broker Server Side passes them locally to the target OPC DA (Data Access), HDA (Historical Data Access) or AE (Alarms and Events) server.
Both machines stay on the same network, but no DCOM communication is required between them.
Figure 1: OPCNet Broker tunnel between an OPC client and an OPC server on the same plant network
A SCADA application needs to read real-time data from an OPC DA server running on another machine in the same plant network.
Instead of configuring DCOM on both machines, the engineering team installs the OPCNet Broker Client Side on the SCADA machine and the OPCNet Broker Server Side on the OPC server machine. The SCADA client then browses and reads the OPC server through the tunnel, with no change to the SCADA application or the OPC server.
The result is a simpler OPC communication architecture that no longer depends on DCOM between machines.
No DCOM configuration for the OPC communication path.
Remove the DCOM openings and associated security settings between machines.
One dedicated communication channel over a single TCP port between the two sides.
Simpler administration of OPC connections, unaffected by DCOM changes from Windows updates or hardening.
A tunnel alone does not make an OPC deployment secure. In production, enable encryption and user authentication on the OPCNet Broker® tunnel, restrict the configured TCP port to approved hosts, use application whitelisting, and harden the machines hosting OPCNet Broker® and the OPC applications. The full checklist is available in the use case "Sharing Custody Transfer Metering Data Between Organizations Without Connecting Their OT Networks".
Talk to an Integration Objects expert about your use case, or request a technical assessment of your OPC architecture.
OPC TunnelingHow OPCNet Broker® secures the OPC links between the OPC servers at each plant and a local data collection application, which forwards the data to a central historian or database, with encryption, authentication and tag-level access control.
OPC TunnelingHow OPCNet Broker® lets OPC clients in an industrial DMZ reach OPC servers in the OT network by opening one TCP port, instead of the multiple dynamic ports DCOM requires.
OPC TunnelingHow producers, pipeline operators and downstream operators exchange custody transfer metering data DMZ to DMZ with OPCNet Broker® and OPC Data Transfer, without connecting their process control networks.