Restarting FTP Uploads and Downloads

  • Article

Applies To: Windows Server 2003, Windows Server 2003 R2, Windows Server 2003 with SP1, Windows Server 2003 with SP2, Windows Server 2008

If your connection closes unexpectedly while uploading or downloading a file using FTP, it might not be necessary to transfer the entire file again, because the IIS -based FTP service supports restarting failed FTP uploads and downloads. If your FTP client software supports FTP restart, you can reestablish the FTP connection and restart the file transfer; and the file transfer will automatically pick up where it left off.

The command-line FTP client included with Microsoft Windows does not support restarting downloads. You must use a third-party command-line FTP client for that functionality. If you are using a command-line FTP client, uploads can be resumed by using the append command to add data to an existing file. Downloads can be restarted by first issuing a rest command with the desired offset, and then issuing the retr command.

Note

The IIS implementation of FTP restart is limited to an offset of less than four gigabytes.

  • For information about installing the FTP service, see FTP Site Setup.

  • For information about the commands supported by the Microsoft Windows command-line FTP client, see the Microsoft Developer Network (MSDN) Web site.

  • For the official FTP specification with the entire FTP command set, see the World Wide Web Consortium Web site.