Anonymous ftp

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1

Hello everybody,

I am currently migrating a project from AS 3.0.90 to AS 4.12,
the CPU from an old 2005 family to a X20CP3687X

The machine has a PC attached that reads/writes data to the PLC via anonymous ftp, i.e. without a user or password.
I have no access to the PC executable, so I need the new PLC to enable anonymous ftp.

Do you know how to configure AS 4.12, AR J4.93?
I have tried the following, trying access using FileZilla client

  • Enabling ftp, but no user => no ftp acess (ECONNREFUSED)
  • Enabling ftp, creating a user without name or password => no ftp access (server responds “password required for user anonymous”)
  • Enabling ftp, creating a user “anonymous” without a password => compilation error in Automation Studio

All I need is the X20CP3687X to behave like the old CP360 with respect to ftp

EDIT: In the meantime I sniffed the communication using wireshark. The old application on the HMI PC sends an empty user, not anonymous.

2

Hi Daniel,

I’m not sure how AS/AR 3.x behaved, but the documentation for AS/AR 4.x makes me think this isn’t possible. I see a note on the Help page for the FTP settings which says:

The FTP server can only be enabled if at least one user has been created

You could try creating a user just to enable the server, and then logging in with the anonymous user rather than the one you created. I see a note in a different section of the documentation which doesn’t sound promising, though this is related specifically to the Web Server:

An explicit username must be used in order to transfer data to the USER partition. This is not permitted to be “guest” or “anonymous”

3

Thanks, Marcus.

Have you read the sentence after “The FTP server can only …”

Der FTP-Server ist im Default AR immer aktiviert und Benutzername/Kennwort werden im Default AR nicht überprüft.

What the heck is this supposed to mean? :slight_smile: It sounds exactly like what I am looking for. What is Default AR? The AR installed on delivery of the CPU?

If so, it should be possible to enable ftp without user.

I was hoping there is a configuration switch accessible via AsArCfg that would enable the old behaviour where old runtimes accepted userless ftp.

4

Hi,

Default AR means the AR BOOT mode which is not booted from the CF / internal flash memory, it’s just the dedicated hardware-integrated system for initial commissioning of the PLC - that’s nothing that can be used for normal runtime (you can think about “default AR” like more or less a “BIOS” of a PC).

Unfortunately I agree with Marcus: the “complete opened FTP door” from very old AR systems is not longer possible at all since years, and cannot be emulated / configured.

Best regards!