Hi Martin,

Thanks for your reply. That's the only additional change I've made and I'm waiting for some feedback to see if that sorted it. I followed a different guide to yours ( https://winscp.net/eng/docs/guide_windows_ftps_server ) but that also suggested using a 5000-5100 as a port range so we'll see if that's what it is!

nick585 wrote:

I'm wondering if it's to do with the range of ports open for data transfer (5000-5100) as it fails suspiciously close to the 5100 mark.

It indeed look suspicious. Did you try to increase the range?

Hello,

Firstly thank you for an excellent application!

I'm having an issue with uploading a large number of image files (200+) to a secure FTP server hosted on a Windows Server 2016 VM.

I'm running WinSCP 5.11.3 (most recent version) on Windows 7. Transfer protocol is Secure FTP. No scripting or automation, and using the default GUI that it installs with. I believe network firewall rules are all in order.

When uploading singular large files, e.g. 300mb+ it seems fine but with large number of small files it disconnects, you get the error message as attached, yet it seems to re-connect and start uploading again on it's own (sometimes you have to manually click reconnect to continue.) I can't confirm if any files get dropped as the client is uploading to a source folder that ingests the files almost immediately into an application. Tested on different connections to rule out individual network issues.

I've attached logs from both the client machine and server (sensitive information modified.)

I'm wondering if it's to do with the range of ports open for data transfer (5000-5100) as it fails suspiciously close to the 5100 mark.

Many thanks in advance for your help!

Nick