Download of file resumes after completed to download more than 100%

[Shawn]

I have a Windows 2003 FTP server that I connect to and download files from on a regular basis. Recently when I download compressed files (zip, 7z, etc) with FileZilla it downloads more than 100%. The process is as follows

• Connect to server
• Browse to folder
• Add 2 or more files to queue (I have 2 concurrent downloads enabled)
• Files download
• Download progress reaches 100%
• Download completes and then resumes and continues download until I force a cancel (I have seen it download 3x the original file size)

Here is a snippet from the FTP log:

Status: Starting download of /sanderson/cdrive/StorageViz/StorageVizCache_EYECATCHERWS2_200808150010.zip
Command: CWD /sanderson/cdrive/StorageViz
Response: 250 CWD command successful.
Command: TYPE I
Response: 200 Type set to I.
Command: PASV
Response: 227 Entering Passive Mode (208,201,252,30,19,151).
Command: REST 52663998
Response: 350 Restarting at 52663998.
Command: RETR StorageVizCache_EYECATCHERWS2_200808150010.zip

If you notice the "restarting" line -- that byte count is the actual file size of the completed download.

Note: I have tried with with a client of Windows XP and Vista

[Tim Kosse]

You are using a Microsoft FTP Server. Those are horribly broken. They actively advertise support for the REST command (resume support), accept REST commands yet still silently ignore them.

You need to upgrade to a proper server.

[Shawn]

I am curious as to why it is not possible to do a sanity check between the file size locally and the file size on the server. Wouldn't this resolve the issue.

While I understand what you are saying about Windows -- it is still one of the most used operating systems around, so it is a little hard to get away from.

[Tim Kosse]

The remote filesize information is unreliable. If a transfer fails for whatever reason (as is the case with your transfers), it has to be resumed.

The only way to fix this is for you to upgrade to a better server.

[scott carl]

I am getting the same behavior using both iis and GlobalScape ftp servers. In addition, I get the same behavior using ws_ftp, curl, and wget.

[Tim Kosse]

If you get the same behavior with other clients, it is definitely not a but in FileZilla.