#769 Synchronize with FTP URL fails

[rmc47]

On trying to synchronize with an FTP URL, I receive the following error:
"The remote server returned an error: (500) Syntax error, command unrecognized."

I am able to open the remote file using "Open URL...", and make changes and save it back to the FTP server, so normal FTP communications seem to work correctly. If the file does not exist on the FTP server, I receive a 550 File Unavailable error, as expected, so the connection to the server is obviously succeeding.

FTP server is ProFTPD, v1.210.

[rmc47]

OK - some further investigation. The first synchronisation after starting Keepass succeeds; thereafter they fail.

Monitoring with Wireshark shows that the FTP connection remains open, and on the second synchronisation attempt, the "USER foo" command is sent again, despite the connection already being authenticated. This results in the error 500 being returned and the sync failing.

[Dominik Reichl]

KeePass 2.11 has been released (which includes a workaround for the 550 error).

Best regards
Dominik

[Eric]

This needs to be reopened... exact same problem - error 500 (without confirming conversation via Wireshark), still present in 2.42.1. File is still accessible and can be loaded manually as a local file but attempts to access it directly via FTP from Keepass continue to fail.

[Dominik Reichl]

Have you tried the IOProtocolExt plugin? This plugin uses a different FTP implementation, which might work better with your server.
https://keepass.info/plugins.html#ioprotocolext

Best regards,
Dominik

[Eric]

Thank you Dominik. It is working again. This has been a recurring problem and I haven't identified how to replicate it on demand. Hopefully this will eliminate it completely and creates a reference for anyone else.