A UA-.NETStandard sample uses ports 51210 for opc.tcp, 51211 for HTTP, and 51212 for HTTPS. After changing them to 31210, 31211, and 31212 in the XML configuration, communication succeeds on the same computer and across a local network running Windows desktop OS, but fails between different fixed-IP hosts running Windows Server OS. The evidence-supported diagnostic is to check Windows Firewall access for the replacement ports.
Port Mapping
| Transport | Default port | Configured port |
|---|---|---|
| opc.tcp | 51210 | 31210 |
| HTTP | 51211 | 31211 |
| HTTPS | 51212 | 31212 |
The source identifies an XML configuration file as the location of these settings, but it does not provide the filename, XML element names, or exact endpoint syntax. Change only the existing port values; do not infer additional configuration keys.
Configure the Replacement Ports
- In the sample's XML configuration, replace 51210 with 31210 for opc.tcp, 51211 with 31211 for HTTP, and 51212 with 31212 for HTTPS.
- On the Windows Server host, configure Windows Firewall to allow the replacement ports required by the enabled server endpoints.
- Point the client at the server's fixed IP and the configured port for the selected transport, then test from the remote computer.
Separate Endpoint Configuration from Firewall Access
Successful operation on the same computer shows that the changed port values can work locally. Failure only when the client and server use different fixed-IP hosts indicates that endpoint configuration alone is insufficient for remote access. Based on the supplied evidence, Windows Firewall is the first control to inspect; the evidence does not establish whether any additional network device or policy is involved.
Verify the Result
Repeat the test with the client on a different fixed-IP host. Confirm that it reaches the exact configured endpoint: 31210 for opc.tcp, 31211 for HTTP, or 31212 for HTTPS. If remote access still fails after the required Windows Firewall ports are allowed, the supplied evidence is insufficient to identify a further product-specific cause.
FAQ
How do I change the UA-.NETStandard default opc.tcp port?
Change the existing opc.tcp port in the sample's XML configuration from 51210 to the required value; the documented case uses 31210. Update the client endpoint to the same port.
Why does the OPC UA server work locally but not from another computer?
The documented configuration works on the same computer but fails between different fixed-IP Windows Server hosts. Open the required replacement port in Windows Firewall and retest the remote endpoint.
Which firewall ports are required after this UA-.NETStandard change?
For the documented configuration, allow the ports used by enabled endpoints: 31210 for opc.tcp, 31211 for HTTP, and 31212 for HTTPS. Do not leave the client configured for the former 51210, 51211, or 51212 ports.
