FluentFTP: 425 Error while transfering data: ECONNABORTED - Connection aborted" after Upload
FTP OS: Windows
FTP Server: FileZilla Server
Computer OS: Windows
I’m using FluentFTP in my application. (Great library by the way.) My application is multi-threaded, with each thread having its own instance of FtpClient but with the same ftp credentials, all connecting to the same FTP server just doing different file-copy or directory listing tasks. All works fine with FTP. I’ve recently done some work on extending this to work with FTPS. Again, works very nicely using a single thread, but as soon as I start using 2 threads (so 2 simultaneous connections) I’m getting an IOException:
Authentication failed because the remote party has closed the transport stream.
On the FTP server (FileZilla Server 0.9.60) I’m seeing this:
(036840)22/06/2018 10:55:19 - brian (10.0.0.26)> 450 TLS session of data connection has not resumed or the session does not match the control connection
I think (and this is pushing the bounds of my knowledge) that the message on the server indicates that the client does not support TLS session resumption. I gather that TLS session resumption acts to prevent a hacker from connecting to the data port before the client does - if the TLS session of the data connection matches the session of the control connection then both the client and server know that the data connection is genuine, whereas a mismatch indicates a potential attack.
I know that I can turn off TLS session resumption in the FTP server - but I don’t want to as it is there to help make the server more secure. Falling back to a single connection is a viable workaround, but since it is faster to use multiple connections it would be nice to find a better way forward.
So: is there a setting that I am missing in FluentFTP to overcome this error?
Thank you.
Logs :
[fluentftp-log.txt](https://github.com/robinrodricks/FluentFTP/files/2127366/fluentftp-log.txt)
[ftp-server-log.txt](https://github.com/robinrodricks/FluentFTP/files/2127362/ftp-server-log.txt)
About this issue
- Original URL
- State: closed
- Created 6 years ago
- Comments: 26 (3 by maintainers)
I am overjoyed. I have reproduced this. I am moving this to a new issue, debug to try and find a fix and will invite you to participate there. It was the COMPLETE log that allowed me to recreate the exact situation. Once again I must plead for maximum verbose complete logs etc. instead of piecemeal information that requires so much back-and-forth.
Agreed and taken note of.
Work in progress, sorry no news yet
Is there any update on this? Later versions of FileZilla have removed the ability to not require TLS resumption and insist that it is absolutely necessary to create a secure connection. Note that other FTP clients (e.g. WinSCP) can connect to this same FTP server and seem to handle TLS resumption from the same computer to the same server.
This bug is due to Fluent FTP is not support “Require TSL session resumption on data connection when using FTP over TLS” Uncheck this item under FTP over TLS Settings on FileZilla Server. Have a try!