# Windows – Why is TFTP ‘PUT’ failing on Windows 7

ftpnetworkingtftpwindows 7windows-vista

I am using Windows 7 RTM, and things are running smoothly for the most part. My Windows 7 installation is the default, out of the box configuration.

I am using the standard TFTP utility available with Windows 7. When I attempt to upload a 3 kb text file to our internal TFTP server, it always time's out. However, TFTP'ing the same file, on XP (from the same network port — different laptop, but same model) it works perfectly.

Is anyone aware of any default configuration on Windows 7 (or even) Vista that could cause this?

There is a warning at the DD-WRT TFTP-Flash page that might be useful.

Recommendations - In order to catch the narrow window for TFTP flash, you should use platforms with simple TCP/IP implementations that don't have CTCP implemented: WinXP or Linux are reported to work, but some are reporting significant problems with Vista, Windows 7 or Windows 2008.

Can you consider using the FTP client?
you would need a FTP server rather than a TFTP server at the other end.

According the the Wikipedia page, the following is supposed to disable CTCP,

netsh interface tcp set global congestionprovider=none


However, what I fail to understand is -- TFTP uses UDP rather than TCP,
So, I don't get how the CTCP problem is related to TFTP.