TIDFTP sending short files goes to timeout

[rlebeau]

I noted that most bytes in the file is #0, and if I change all the #0 with other value then the file is sent without error.

TIdFTP doesn't care what the file's bytes are. It just reads the file's raw bytes and sends them as-is.

Other thing: all the FileZilla servers that does this error are running in Windows 11 PRO virtual machines that are running into a LINUX-PROXMOX environment. If I send the same file to the same version of FileZilla but running in other Windows environments, then the file is sent without problems.

That sounds like an environmental issue and not an Indy issue. Have you reached out to the FileZilla devs?

Here you have the logfile done on the client-side. First it creates a target folder, then if the file already exists it is delteted, then the file is sent.

I don't see anything out of the ordinary in that log, except for the missing final response to the file transfer, which is where the timeout error is occurring. TIdFTP is sending the file, but the server is not finalizing the transfer.

Let me add another thing: all the servers that cannot receive this file from a TIdFTP client, can receive the same file using any other client.

That makes no sense.

Have you tried using Wireshark to capture the raw TCP traffic? Make sure TIdFTP is actually transmitting all of the expected file bytes over the data connection, and that a closure of the data connection (FYN packet) is being transmitted at the end of the transfer.

I add here an image I get when debuggin Indy code, I think this mean Indy is sending the all the bytes.

All that means is that the file bytes are being given to the socket. It is then up to the OS to make sure they are actually transmitted to the server.