You can test your tunnelling connection like this:
Ensure that you have correctly configured the DataHub instance on the OPC server machine and the OPC client machine.
Start the DataHub instance on the OPC server machine if it is not running already. It should start up the OPC server on that machine.
Start the OPC client on the OPC client machine. It should start the DataHub instance, and once the connection has been established the data from the OPC server should be visible in the OPC client.
You can view connections with the Connection Viewer.
If you don't see data in your OPC client, double-check the following:
The DataHub configuration on both machines.
The functioning of the OPC server and client.
The physical network connection.