Dear

I have a project in WinCC v7.5 SP2 Upd.18 and there is a problem with it.

The clients randomly disconnects from the server for 5seconds and then they all come back.
This happens sometimes like 20times in a day and sometimes 2times.
Every time when this happens, there is something in the log files from wincc (PM_Diagnose.log).
The logfile is in the attatchements. (starttime: 2025-02-26 14:10:42.160 PM)
It seems like wincc is fully restarting.
I have tried so many things that I do not know what to do.
The main things that I did where:
* Reinstall WinCC both client and server.
* Reset WinCC through script.
* Check network adapter settings for power savings. (everything seems good)
* Make sure all unnecessary services are disabled.
* All users are in the same group from windows.
* asked the IT-department to check the network traffic. (nothing unusual)
* Made a test setup with 1client and 1server en no switch in between.
        data still comes in the log file.
* Made a new project with nothing in it and there still comes data into the log file
* runs continuously a ping command. (pings just fine when it happened in the log file)

Does have anyone an idea what this could be and what I can do to fixes this?

This would be really helpful because I really have no clue anymore.

Thanks In advance

Hello

* all clients and server has the same version and update.
On the real clients/server is it v7.5 SP2 Upd.15 and on the test setup is it v7.5 SP2 Upd.18.
This was for testing purpose.

* I start the project normally through autostart from Siemens.
On the test setup I mainly use on the server just startup manual the wincc explorer and then runtime.
The clients is through interconnect.

* WinCC and his client are in a different subnet and also have each own network card in the PC.

* It is hard to really get some logs, because I do not know when this happens.
I have taken some screenshots in between the problems, but I didn't saw anything unusually at that time.

* There is no external antivirus installed on the PC and I have set the firewall of in windows.
This is something what must be done here with this kind of PC's.

I really have no clue what this can be, it drives me a bit crazy.

Thank you already for your help

Hello Murof,

Thank you for trying to help me.

I will do every step again from the FAQ as soon as possible.

The computers are all visible from each station.

I will come back to this post when I have tried the FAQ.

Thank you in advance

Dear

I am sorry to say that the FAQ's didn't work for me.

I did them both on the 2 pc's in the test setup and I got back the messages in the logging file that the client has restarted the runtime.

I am so confused.

Do you have any idea's what it could be please?

Thank you in advance

Dear

I have changed the name from the PC after installation, but only on the client side if I am correct.
I have setup this PC's a while back, but we work here with Images from PC's for when the PC's goes down we have a backup.

I have talked with the IT departement about this problem and gave them a pcap from wireshark. The data is encrypted so we could not see what was send, but we found that the server pushed a message to the client and the client his response was 3seconds late then. After the server resend there package (after timeout) for 2x times, the client PC is always late and the server resets the TCP connection. All of this communication is on TCP protocol.
I have put a screenshot in the attatchments from wireshark.

We do not know why this message from the client is suddenly late and other times not.

Do you have any suggestions please.

I want to thank you already for all you effort

Hello Murof

It is a really annoying problem. It drives me a little crazy.

I have put the IP adresses from the server and client in the multicast proxy selection (simatic shell).
I did this both on the server en client PC.

I have no idea if this is gonna work, but I will give it a try.

The next step I think is tho wipe the entire PC with a fresh windows install and then reinstall everything.
Do you think this could help?

Or do you have any other suggestions mayby?

Thank you in advance