SSH and Telnet over Ethernet problem

[Joze]

We recently had a problem where we remotly tried to update a small portion of Codesys code (we don’t really do this but this was a special, testing only case where everything was secure). When updating Codesys runtime crashed and we couldn’t remotly login again. The idea then was to SSH into the PLC are remotly reboot it.

We SSH-ed into the router and then form the router tried to SSH into the PLC. Reading beck’s instructions told us that the default username/password combination is ssh/ssh. The username and password were accepted BUT after login the terminal simply freezes.

We then tried the same thing with telnet (defaults are tel/tel) and the same happens. We trid using Putty, Win32-openssh and chiptool terminal and the same problem occurs.

What could be the problem here? It would be quite useful if it was possible to remotly reboot the PLC. We are using VPN to connect to the PLC, so it should be secure.

[Sergio Bertana]

When you connect to the system by telnet, by default the standard I/O terminal is the system shell, so no prompt is displayed on the telnet screen. To change the standard I/O terminal you must send the Ctrl+F command according to the IEC61131-3 programming Manual, at the moment this manual is only in Italian, anyway here an abstract in English of the telnet chapter.

After the focus is on the telnet terminal you can send the REBOOT command to the system.

[Autore]

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