"Resume" unsafe with SSH Server

Concerns WinSCP versions newer than 3.5.6, connecting to Tectia SSH Server.
The "resume" feature is unsafe and the uploaded file is corrupt.

If a file upload is interrupted twice, on the second "resume", the upload will finish instantly and apparently successfully - even when not all of the remaining bytes have been sent. The result is a corrupt file.

In contract, WinSCP 3.5.6 "resume" works perfectly with any number of interruptions.

Additional info follows,
Session protocol = SSH-2
SSH implementation = 5.3.9.3 SSH Tectia Server
Encryption algorithm = aes
Compression = No
File transfer protocol = SFTP-3
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Additional information
The server supports these SFTP extensions:
newline@vandyke.com=0x0A

What version of SFTP do you use with "newer versions"?
What kind of file it is? Text of binary?

Hi Martin,

I tested against these servers, SSH Tectia Server 5.3.9.3 and 6.06.19(latest release).

Winscp reported the file transfer protocol as SFTP-3.

Examples of newer versions that did not work - winscp405.exe, winscp415.exe, winscp418.exe. These would produce a corrupt file on the 2nd resume.

I tested using binary files, i.e. zip files which I can easily test for integrity afterwards.

Thanks
Thiam

Can I have a test account on the server?

Martin,I have created the test account and sent the credentials to the email address listed in your profile. Thanks

songtm wrote:

Martin,I have created the test account and sent the credentials to the email address listed in your profile. Thanks

Thanks. I have sent you an email with a request for more details.

This issue has been added to tracker.

I have a client who is also experiencing this problem. Can you supply any updates on this issue?

ccamp wrote:

I have a client who is also experiencing this problem. Can you supply any updates on this issue?

It has been fixed already as you can see in the tracker.