Cannot write file "sync.ffs_db.1c22.ffs_tmp"

[mdrmdr]

What could cause this error?

19:48:11     Error:     Cannot write file "ftp://ftp.XXX.de/sync.ffs_db.1c22.ffs_tmp".
CURLE_PARTIAL_FILE: server did not report OK, got 450
450 Transfer aborted. Link to file server lost [curl_easy_perform]
19:48:11     Error:     Stopped


It only and always happens with ffs_tmp files. All other files synced to the ftp-root directory work fine even that the above error is displayed. So its most likely not a permission problem. It seems that sync.ffs_db is not updated. The error does not occur when Directory on server is not root but a sub-directory.

I'm using FFS 11.10 (donation version). The ftp-server is a Linux server on all-inkl.com.

[mdrmdr]

Nobody an idea?

Guess viewtopic.php?t=8272 is the same problem!

Now I get the above curl error even on transfers to sub-directories. This time the file which cannot be written is "ftp://xxxxxxxx.kasserver.com/scripts/tools~1be6.ffs_tmp" (the IP of the server is the same as in my initial post). With this error, I cannot use FFS anymore... :-(

I always try the same file action with FileZilla, where no problem at all occurs...

[mdrmdr]

For testing purposes, I tried to sync the same files to my Raspberry Pi 4. Same error!

On the Pi 4, I can enable a full detail log of the ftp server. See attachment.

The error always is similar to following:

Transfer aborted after 63832064 bytes in 1.96 seconds
notice: user root: aborting transfer: Link to file server lost


I also disabled Windows Defender and the Windows Firewall. No success.
Attached is the full log of the Pi 4 ftp server (ProFTPD).

Since this now happens to more than one ftp server and if I copy the same files with FileZilla without any problems, I strongly assume FFS has a new problem with syncing to Linux hosts. It might be a timing issue, since sometimes it works... Please help!

[Zenju]

Do you know which TLS version your FTP server is using? If it's TLS1.3, then this might be the following curl bug: https://github.com/curl/curl/issues/6149

To check, you could try the following FFS version which limits TLS to version 1.2 and see if this works: https://www.mediafire.com/file/ny8hy3n5l6corxk/FreeFileSync_11.12_%255BBeta%255D_Windows_Setup.exe

[mdrmdr]

Don't know for sure. Installed is ProFTPD 1.3.6c-2 (Ubuntu). The config file says "ALL -SSLv3 -TLSv1 -TLSv1.1". So I assume TLSv1.3 is used once the client supports it.

Thanks for the beta version. I'll test it today at night and report here.

Update 10:49: Could already test the beta during a work break. Looks good. Did some syncs to the remote ProFTPD and to my own local Raspberry Pi based ProFTPD server (with TLS) and no errors so far.

If on my own ftp server only TLSv1.3 (no TLSv1.2) is allowed, the error in the attachment shows up.

[Zenju]

Okay, here's a FFS version without the TLS 1.2 limit and including the fix mentioned in the github link:
https://www.mediafire.com/file/khfra8dj930xnru/FreeFileSync_11.12_%255BBeta%255D_Windows_Setup%25282%2529.exe

Does it work on both your test systems?

[mdrmdr]

Works on local server, which is ProFTPD 1.3.8rc1 now, with TLS 1.3 and TLS 1.2.
Fails on remote server with the error in the attachment. Seems not to work with 1.3. Installed the version with the 1.2 limitation again and that worked.

[mdrmdr]

Hope FFS 11.12 is released today, since my donation subscription ends today 11:59 pm ... ;-)

[mdrmdr]

Unfortunately the error is still in 11.12...

[Zenju]

libcurl 7.78 just released with several related fixes. Might be worth another test: https://www.mediafire.com/file/smakh9ewg7m6kip/FreeFileSync_11.13_%255BBeta%255D_Windows_Setup.exe

[mdrmdr]

Same error with the 11.13 beta. A cause could of course also be that the hoster does not use the most recent version of ProFTPD. But they are not willed - and I can understand that - to move away from the Ubuntu standard package version. It works, also with 11.12, with my Raspberry and the newest ProFTPD. And of course it works without TLS in all cases.