ftp problem: download OK, upload essentially fails

[kswenson6206]

I have a strange problem with FTP. I can connect to the site, i can browse through folders, I can download files no problem, but uploading seems to sort of freeze up. That is, it never gives an error but it sits there mostly looking stuck, except every 30 seconds or so it claims to send a bit more. If I wait 10 minutes it might send about 12K bytes or so. The file grows on the server, but I have no idea if the data in the files are correct or not.

A little background: I have been using Total Commander exclusively for FTP for about 10 years. Currently using 64bit version 8.5. I have used it with this particular site many times. Last week a hard disk died, and I had to re-install the entire operating system (64 bit Win 7) and of course all the software.

Since the complete reinstall of everything, I am getting this funny behavior. I have tried with and without PASV mode -- no difference.

Some setting is probably wrong, but any suggestions on how to go about testing for what might be wrong?

the FTPLog looks like this:

Code: Select all

1:227 Entering Passive Mode (205,178,152,41,46,196).
1:APPE Portrait_BHartman.png
1:125 Data connection already open; Transfer starting.
1:Upload
1:Upload: 13,823 bytes
1:OFFLINE4, no reply
1:----------
1:Connect to: (04/13/2014 16:57:55)
....(lots of lines snipped out)
1:227 Entering Passive Mode (205,178,152,41,48,242).
1:APPE Portrait_BHartman.png
1:125 Data connection already open; Transfer starting.
1:Upload
1:Upload: 15,359 bytes
1:OFFLINE4, no reply
1:----------
1:Connect to: (04/13/2014 16:58:37)

It seems to try to send a chunk, and then this OFFLINE4 appears, it then appears to automatically try to reconnect, and upload a few more bytes. Each cycle gets a bit bigger.

As a test, I transferred a 4-byte text file, and this worked OK. Then a 1170 byte text file worked OK. The an 2340 byte file -- froze up, timed out, tried again, and then failed with "Upload size mismatch!" error. Indeed, it seems to have produced a 5996 byte file. Downloading that show it to be corrupted (fragment lines and repeated lines).

Another test: on a different client machine (laptop, 64bit Win7) using Total Commander 8.01 I am able to upload to that server without limitation.

Another test: I installed 8.51_rc1 and tried (on the machine with the new OS) and it has the same halting behavior.

I have used Total Commander with this site often in the past. It is unlikely there is any problem with the server. It is more likely something wrong either with my newly installed OS or my newly installed Total Commander on my end.

Update 4/14 - It gets stranger. If I reboot the computer and use the windows command line ftp it works. But then when I try to use TotalCommander, it blocks and fails (on files larger than ~2K). At that point, the windows FTP client also fails, and continues to fail until I reboot the machine. This is clearly an OS problem, but something in the attempt to FTP with TotalCommander triggers is.

Similar problem described but fixed two years ago: URL STRIPPED OUT BY FORUM, but it is a windows support link

[ghisler(Author)]

OFFLINE4 is due to a data connection timeout (no reply for more than 10 seconds). Some local firewall and virus scanners can cause this: They take the entire upload, scan it, but send it only when the file is completely in their possession and scanned.

Try increasing the timeout from 10 seconds to a higher value, e.g.:
wcx_ftp.ini
[General]
DataConnectTimeout=60

[kswenson6206]

When the upload of the 99K file is successful, it completes in about 4 seconds (using the command line ftp client). These are not "large" files. However, when it goes into non-functional mode, then apparently the connection is being interrupted in much less than 4 seconds. It is immediately apparent that no data is flowing in less than one second. Eventually, it does time out, but it is not because it needs more time. Something has interrupted the connection. And it only happens after something changes something.

[ghisler(Author)]

There are firewalls with a content filter which will interrupt an outgoing transmission when a file contains certain keywords or data like credit card numbers.

If your FTP server supports encryption, you should try to turn that on (then the filter cannot see the content, and will not filter it).

[kswenson6206]

Thanks for the attention and a couple of good suggestions. The problem magically disappeared and I suspect it was a low-level driver problem and we may never know what. After installing an HP Printer software -- whether this had anything to do with it we will never know -- the FTP started working without any problem. My guess is that TotalCommander was doing something legitimate that triggered a driver problem that remained in effect until the machine was rebooted.

Thanks again for an excellent and invaluable product.