Firewall test
- Last UpdatedMay 29, 2025
- 2 minute read
Perform a firewall test with Telnet
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From a separate node from where the OPC UA Server service is running, enable Telnet by turning on the Telnet Client Windows Feature.
Note: This test is ideally run from the OPC UA client node.
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Open the Windows Control Panel.
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Go to Programs and Features, then select Turn Windows features on or off.
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Scroll down the list of features to Telnet Client and enable it. Telnet is disabled by default.

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Prior to running this test, verify that WindowViewer is running. If the OPC UA Service Host is configured, WindowViewer will start the InTouch OPC UA Service. See Configure the InTouch OPC UA Server for details.
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Run Telnet in a command window on the OPC UA client node by entering the following:
telnet <nodeName or ipAddress> <portNumber>
where
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nodeName is the machine name of the InTouch HMI run-time node. Use nodeName or ipAddress, not both.
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ipAddress is the IP address of the InTouch HMI run-time node. Use nodeName or ipAddress, not both.
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portNumber is the port number you configured in InTouch HMI for the OPC UA Service. The default port number 48032.
Example: telnet 10.10.10.06 48031
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If the command is not successful, it will time out with a message stating that the connection failed. In this case, go to Configure the run-time node firewall.
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If the telnet command is successful, the command prompt changes to a Telnet prompt.

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If the Firewall Test is successful, configure the OPC UA client and OPC UA server certificates. The next step in setting up your OPC UA connection depends on if you are using a third-party OPC UA client application, or the OPC UA connection available with Gateway Communication Driver.
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