Connection fails during SSL init

Open jwalt opened this issue 6 months ago • 1 comments

I am trying to connect to an S7-1200 that is running a TIA V17 project, firmware 4.5. Looking at a wireshark dump, the PLC responds to InitSSL with return value 0 (OK). The very next packet is a TLS1.3 ClientHello, with no response from the PLC at all. I also tried commenting out the TLS1.3 config, then I get a TLS1.2 ClientHello and no response either. What can I do to debut the situation?

Jun 06 '25 23:06 jwalt

Hi, do you also have the CPU with with firmware version 4.5 in your TIA project? But if I remember correctly, if you have confgured a non-TLS firmware in the TIA project, then the CPU denies the InitSSL request.

What you can try for analysis, is to create a Wireshark capture when TIA is connecting to the PLC. If it's using TLS, and if there's a major difference in the Client Hello.

Jun 09 '25 15:06 thomas-v2