Microsoft KB Archive/891371

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

Article ID: 891371

Article Last Modified on 11/1/2006

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APPLIES TO


 * Microsoft Windows Server 2003, Standard Edition (32-bit x86)
 * Microsoft Windows Server 2003, Enterprise Edition (32-bit x86)
 * Microsoft Windows Server 2003, Datacenter Edition (32-bit x86)

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Important This article contains information about modifying the registry. Before you modify the registry, make sure to back it up and make sure that you understand how to restore the registry if a problem occurs. For information about how to back up, restore, and edit the registry, click the following article number to view the article in the Microsoft Knowledge Base:

256986 Description of the Microsoft Windows Registry



SYMPTOMS
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.



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



RESOLUTION
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:  Click Start, click Run, type regedit, and then click OK. Locate and then click the following registry subkey:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters

 Right-click Parameters, click New, click DWORD Value, and then type TcpWindowSize as the name of the value. Right-click TcpWindowSize, click Modify, and then type a hexadecimal value of ffff or a decimal value of 65535 . Click OK. Quit Registry Editor.</li></ol>

<div class="moreinformation_section">

To determine the download speed on your computer
<ol> Install a Microsoft Internet Information Services (IIS) server.</li> Make sure that the FTP service is running on the server.</li> Enable anonymous access on the FTP server.</li> Download a file to the FTP root. To do this, follow these steps: <ol style="list-style-type: lower-alpha;"> Click Start, click Run, type cmd, and then click OK.</li> At the command prompt, type the following:

ftp ComputerName

</li> When you are prompted for a user name and for a password, type anonymous for both entries.</li> Type the following commands at the command prompt. Press ENTER after each command.

hash

get filename.extension

</li></ol> </li></ol>

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).

<div class="status_section">

STATUS
Microsoft has confirmed that this is a bug in the Microsoft products that are listed in the &quot;Applies to&quot; section.

Keywords: kbprb kbbug KB891371

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