TOPIC: opc ua connection to http://open62541.org/

Hello,

I downloaded TeslaSCADA 2.0 and tried to connect to our OPC UA server (from open62541.org/)
When I clicked on ... I got connection error message.

I can connect to this opc ua server with UAExpert (and several other opc ua clients)

I have recorded tcp traffic with smartsniffer (txt- and mht-file have the same content)

Please have a look. Thank you very much.

Regards

Franz

We've already been asked about OPC UA server based on this library. Discussion you can find here: github.com/open62541/open62541/issues/689.
They've solved the problem in their library and it starts working with our product - TeslaSCADA. I don't know what they've changed in the library again or maybe you've made some mistakes in your server implementation. Try to discuss with their support team. If you still will have problems send us your server.

Best regards,

Ruslan

Hello Ruslan,

as I expected they say that it is not their fault....

Their comment was:
"The TeslaScada client is sending a CloseSecureChannel request as a normal message (MSG prefix).
They should send the CloseSecureChannel request with a CLO prefix."
See attached png-file.

Kind regards

Franz

PS: you can download their opc ua server here open62541.org/ (I tried windows 64 bit). There is a folder example where a binary server can be found.

Hello Franz,
Supporters of Open62541 have written to me six months ago and send me OPC UA server written on their code. We've solved the problem together and according their messages: github.com/open62541/open62541/pull/707#issuecomment-233645668 TeslaSCADA works with their server based on their C stack. As I remember the problem was that our OPC UA client demand not NULL server certificate. According messages in the forum: github.com/open62541/open62541/issues/689. the users also can possibility to connect to their server by using TeslaSCADA products.

Best regards,
Ruslan

Hello Ruslan,

Julius from the open62541 project here.
The issue is different from the NULL server certificate.

The current Tesla Scada implementations sends CloseSecureChannel messages with the wrong message prefix (MSG instead of CLO).
This is not conform to the OPC UA specification. Please take a look at the screenshot frax22 attached to his last post to see this in action.
I attached a wireshark capture with more details to this post.

We would like to support Tesla Scada. But we feel that the fix should happen on your side.
Do not hesitate to ask if you have further questions.

Best regards,
Julius

Hello Julius,

OK. We'll take a look, but it's strange because last time when we've tested with server based on your stack all worked.
It will be very helpful if you send server based on your stack.

Best regards,
Ruslan