Microsoft KB Archive/911162

= Error message when you use an FTP client in Windows XP: &quot;500 Invalid PORT Command&quot; =

Article ID: 911162

Article Last Modified on 8/29/2007

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APPLIES TO


 * Microsoft Windows XP Professional
 * Microsoft Windows XP Home Edition

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SYMPTOMS
When you use an FTP client on a computer that is running Microsoft Windows XP, you may receive the following error message:

500 Invalid PORT Command

This problem occurs when Windows Firewall is enabled on the network connection.



CAUSE
This problem occurs because the Application Layer Gateway Service for Windows XP does not recognize TCP ports that are lower than 1025 as valid FTP ports. When the FTP client uses a port that is lower than 1025, the FTP host receives an invalid port command. Therefore, the FTP connection cannot be established.



Hotfix information
A supported hotfix is now available from Microsoft. However, this hotfix is intended to correct only the problem that is described in this article. Apply this hotfix only to systems that are experiencing this specific problem. This hotfix might receive additional testing. Therefore, if you are not severely affected by this problem, we recommend that you wait for the next service pack that contains this hotfix.

To resolve this problem, submit a request to Microsoft Online Customer Services to obtain the hotfix. To submit an online request to obtain the hotfix, visit the following Microsoft Web site:

http://go.microsoft.com/?linkid=6294451

Note If additional issues occur or any troubleshooting is required, you might have to create a separate service request. The usual support costs will apply to additional support questions and issues that do not qualify for this specific hotfix. To create a separate service request, visit the following Microsoft Web site:

http://support.microsoft.com/contactus/?ws=support

Prerequisites
No prerequisites are required.

Restart requirement
You must restart your computer after you apply this hotfix.

Hotfix replacement information
This hotfix does not replace any other hotfixes.

File information
The English version of this hotfix has the file attributes (or later file attributes) that are listed in the following table. The dates and times for these files are listed in Coordinated Universal Time (UTC). When you view the file information, it is converted to local time. To find the difference between UTC and local time, use the Time Zone tab in the Date and Time item in Control Panel.



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



MORE INFORMATION
When this problem occurs, Network Monitor may show that the port command that the FTP client uses is 0,0,0,0,0,0.

For more information about the Application Layer Gateway Service, visit the following Microsoft Web site:

http://msdn2.microsoft.com/en-us/library/ms998420.aspx

For more information about the terms that are used in this article, click the following article number to view the article in the Microsoft Knowledge Base:

824684 Description of the standard terminology that is used to describe Microsoft software updates

Keywords: kbftp kbfix kbhotfixserver kbqfe kbpubtypekc KB911162

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