The FTP connection does not use all available bandwidth to download a file in Windows Server 2003

When you download a file from a File Transfer Protocol (FTP) server in Microsoft Windows Server 2003, the FTP connection does not use all available bandwidth. However, when you use Microsoft Windows 2000 to download the same file, the FTP connection uses all available bandwidth.

By default, the TcpWindowSize registry value is smaller in Windows Server 2003 than in Windows 2000.

Warning If you use Registry Editor incorrectly, you may cause serious problems that may require you to reinstall your operating system. Microsoft cannot guarantee that you can solve problems that result from using Registry Editor incorrectly. Use Registry Editor at your own risk.

To resolve this problem, follow these steps on your Windows Server 2003-based computer:

1. Click Start, click Run, type regedit, and then click OK.
2. Locate and then click the following registry subkey:
   HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters
3. Right-click Parameters, click New, click DWORD Value, and then type TcpWindowSize as the name of the value.
4. Right-click TcpWindowSize, click Modify, and then type a hexadecimal value of ffff or a decimal value of 65535.
5. Click OK.
6. Quit Registry Editor.

To determine the download speed on your computer

1. Install a Microsoft Internet Information Services (IIS) server.
2. Make sure that the FTP service is running on the server.
3. Enable anonymous access on the FTP server.
4. Download a file to the FTP root. To do this, follow these steps:
   1. Click Start, click Run, type cmd, and then click OK.
   2. At the command prompt, type the following:
      ftp ComputerName
   3. When you are prompted for a user name and for a password, type anonymous for both entries.
   4. Type the following commands at the command prompt. Press ENTER after each command.
      hash
      get filename.extension

At the end of the transaction, an average speed for the download is displayed.

Note For best results, download a file that is larger than 200 megabytes (MB).

Microsoft has confirmed that this is a bug in the Microsoft products that are listed in the "Applies to" section.