Advanced OPC Data Logger

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For Windows 2000 - Windows 11 (2022) (incl. Server, x86 and x64). Latest version: 3.10.0 build 306. March 6, 2024.


OPC and DCOM Configuration. Configuring the Windows 2008 and Windows 7 firewall for DCOM and OPC

OPC and DCOM Configuration on Windows 2008 and Windows 7

3. Configuring the Windows 2008 and Windows 7 firewall for DCOM and OPC

The DCOM technology the OPC technology is based on uses reserved system port 135 for its work. For servers and clients to run normally, you should permit these connections in your firewall. If the client and the server are located on different computers, firewall configuration is required. Below you can see an example of configuring the standard firewall in Windows 2008. If the client and the server are used on one computer, there is no need to configure the firewall.

Access to the computer or server management console
Fig. 11 Access to the computer or server management console

For Windows 7 users. To open the firewall management console, use "Start" - "Control Panel" - "System and Security" - "Windows Firewall" - "Advanced settings" or run it from the command line with the "wf.msc" command.

For Windows 2008 Server users. To open the firewall management console, you may use the "The server management console" or run it from the command line with the "wf.msc" command.

3.1 Permitting DCOM activity

By default, Windows blocks inbound connections from other computer. For OPC clients to be able to connect to OPC servers on this computer, enable the corresponding rule.

Firewall rule properties
Fig. 12 Firewall rule properties

Permitting DCOM activity
Fig. 13 Permitting DCOM activity

For Windows 7 users. If the "COM+ network access" or "DCOM" rule is not in the list, create two "Port" rules.

  1. Port 135 rule for the TCP protocol;
  2. Port 135 rule for the UDP protocol;

3.2 Creating rules for every OPC server

You need to permit activity for every OPC server running on this computer. Also, you should permit network activity for the OpcEnum system service that allows remote clients to receive the list of servers from this computer.

Below you can see an example of how to create a rule for OpcEnum. Rules for other applications are created in a similar way.

Adding an individual rule
Fig. 14 Adding an individual rule

  1. Select the "New Rule" action;
  2. Select the "Program" rule type;
  3. Click the "Next" button.

Selecting the file
Fig. 15 Selecting the file

  1. Select the "Program Path" option;
  2. Specify the full path to the program and its file name;
  3. You can select the program on the disk using the "Browse" button;
  4. Click the "Next" button.

Rule properties
Fig. 16 Rule properties

Active profiles
Fig. 17 Active profiles

Rule name
Fig. 18 Rule name

Active rules
Fig. 19 Active rules

You should repeat these steps to create a rule for every OPC server.

Related articles:

OPC and DCOM Configuration on Windows 2008 and Windows 7

OPC and DCOM Configuration on Windows Server 2012 and Windows 8