Hello OPC Labs,
I have a problem with connecting my OPC-Client (and others like Matrikon OPC Explorer) to a remote server. The server I am trying to connect to is a Siemens WinCC. I already managed to browse the server list and I can even "connect" to the server with the Matrikon client. But as soon as I try to browse items, it fails (both clients). From QuickOPC I get the message "Access Denied" which usually comes from incorrect DCOM settings. To clarify the settings I list them below:
- server default authentication level: Connect
- server default impersonation level: identify
- WinCC authentication level: Standard (also tested Connect)
- WinCC identity: interactive user
- The user on client and server share the same name and password
- The user has full permissions for the WinCC and for system (dcomcnfg limits and standard)
- Firewall-Port 135 is open on the server and client
The last two days I tried solving the problem with reading documentations and forums. When I tested with the Matrikon OPC Explorer I got the following Error:
Application ...\Matrikon\OPC\Explorer\OPCExplorer.exe with PID b0c is requesting to activate CLSID {75D00BBB-D...} on computer [...] with default activation authentication level at 2. The lowest activation authentication level required by DCOM is 5(RPC_C_AUTHN_LEVEL_PKT_INTEGRITY). To raise the activation authentication level, please contact the application vendor.
This made me think about, what if the WinCC-Server itself requires RPC_C_AUTHN_LEVEL_PKT_INTEGRITY (5) as authentication level and ignores the system settings? I am no professional when it comes to DCOM so I don't know if this is even possible. I then searched the forums and got to the following topic:
DCOM permissions and UseCustomSecurity, TurnOffActivationSecurity, and TurnOffCallSecurity
. This leads me to think, that the maximum authentication level in QuickOPC is 2 (Connect). This would explain why I can't browse the server.
Now is there a way to raise the authentication level or am I stepping on the wrong path here and that is not the problem? And to mention, I tried a few combinations of UseCustomSecurity, TurnOffActivationSecurity, TurnOffCallSecurity but had no success.
Please advise me on how I can solve the problem. If any additional information is required, feel free to ask.
Best Regards
ToSi