Answer question

800xA 5.1: error when adding a remote OPC node ("could not access the specified computer!") - firewall isse?

See the attached screenshot. I get the following error when trying to add a remote OPC server:

"Could not access the specified computer! Error: The network path was not found. (0x80070035)".

There is a firewall between the OPC node and the connectivity server, and I think this is the reason for the error.

I need to know exactly what services/ports need to be allowed in the firewall for this to work. I know port TCP 135 for DCOM/OPC must be open, but what else?

(I have already tested the OPC connection between the connectivity server and the remote OPC server node using a third-party OPC client and it does work.)