Error message when you use an FTP client in Windows XP: "500 Invalid PORT Command" (911162)


The information in this article applies to:

  • Microsoft Windows XP Professional
  • Microsoft Windows XP Home Edition

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.

RESOLUTION

Hotfix information

A supported hotfix is now available from Microsoft, but it is only intended to correct the problem that is described in this article. Only apply it to systems that are experiencing this specific problem. This hotfix may receive additional testing. Therefore, if you are not severely affected by this problem, we recommend that you wait for the next Windows XP service pack that contains this hotfix.

To resolve this problem immediately, contact Microsoft Product Support Services to obtain the hotfix. For a complete list of Microsoft Product Support Services telephone numbers and information about support costs, visit the following Microsoft Web site:

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

Note In special cases, charges that are ordinarily incurred for support calls may be canceled if a Microsoft Support Professional determines that a specific update will resolve your problem. The usual support costs will apply to additional support questions and issues that do not qualify for the specific update in question.

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.
File nameFile versionFile sizeDateTime
Alg.exe5.1.2600.281144,54414-Dec-200501:08

STATUS

Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" 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://technet2.microsoft.com/WindowsServer/en/library/cef3f325-ef6b-494c-be03-99103d5246e91033.mspx?mfr=true

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

Modification Type:MajorLast Reviewed:8/29/2006
Keywords:kbFTP kbfix kbQFE kbhotfixserver kbpubtypekc KB911162 kbAudITPRO
©2004 Microsoft Corporation. All rights reserved.