You Cannot Connect to External FTP Sites by Using a WRQ Reflection FTP Client through ISA Server 2000 (829892)


The information in this article applies to:

  • Microsoft Internet Security and Acceleration Server 2000

SYMPTOMS

When you use a WRQ Reflection FTP client that is configured to use the SOCKS version 4 protocol, you may not be able to connect to external FTP sites through Microsoft Internet Security and Acceleration (ISA) Server 2000. The FTP client displays the following error message:
A connection can not be established. Please try again.

CAUSE

The SOCKS version 4 Reflection FTP client spreads its SOCKS CONNECT request over two TCP segments. The built-in SOCKS application filter in ISA Server does not handle this correctly, and the SOCKS connection fails.

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 Internet Security and Acceleration Server 2000 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

To install this hotfix, you must have ISA Server Service Pack 1 (SP1) installed on your computer. For additional information about how to obtain the latest ISA Server service pack, click the article number below to view the article in the Microsoft Knowledge Base:

313139 How to Obtain the Latest Internet Security and Acceleration Server 2000 Service Pack

File Information

The English version of this hotfix has the file attributes (or later) 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 tool in Control Panel. 
Date         Time   Version       Size    File name
------------------------------------------------------
09-Oct-2003  15:22  3.0.1200.295  34,064  Socksflt.dll
This fix also applies to the French, German, Spanish, and Japanese versions of ISA Server.

STATUS

Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section of this article.
Modification Type:MinorLast Reviewed:10/26/2005
Keywords:kbHotfixServer kbQFE kbHotfixServer kbQFE kbbug kbfix KB829892
©2004 Microsoft Corporation. All rights reserved.