FIX: Connections to a Web site that was published by ISA Server 2004 may fail and you receive a connection time-out error

Consider the following scenario:

• You publish a Web site by using Microsoft Internet Security and Acceleration (ISA) Server 2004.
• You configure the Web publishing rule to Requests appear to come from the original client.

In this scenario, the requests that are forwarded by ISA Server 2004 to the Web server may fail, and you receive a connection time-out error.

A previously-closed client connection is recreated with ISA Server 2004 after ISA Server 2004 closes a session to the Web server. Generally, ISA Server 2004 immediately tries to reestablish the session on behalf of the same client by using the original IP address and port.

This problem occurs because ISA Server 2004 reestablishes the session by using the original client IP address and port. This behavior may cause the Web server to reject the new connection because the Web server has not cleaned up the state of the previous connection that was made by using the previous client IP address and port.

Hotfix information

A supported hotfix is 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.

If the hotfix is available for download, there is a "Hotfix download available" section at the top of this Knowledge Base article. If this section does not appear, submit a request to Microsoft Customer Service and Support to obtain the hotfix.

Note If additional issues occur or if 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. For a complete list of Microsoft Customer Service and Support telephone numbers or to create a separate service request, visit the following Microsoft Web site: Note The "Hotfix download available" form displays the languages for which the hotfix is available. If you do not see your language, it is because a hotfix is not available for that language.

Prerequisites

You must have ISA Server 2004 Service Pack 3 (SP3) installed to apply this hotfix.

Restart requirement

You must restart the 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.
After you install this hotfix, you have to follow these steps to enable it:

1. Start Notepad.
2. Paste the following script into the Notepad file.
   
   Note The value that is specified by this script sets a delay (in milliseconds) between closing a connection and reestablishing it from the same port. You may have to adjust the values that are based on your environment. By default, there is no delay before you run the script.
   

   Const SE_VPS_GUID = "{143F5698-103B-12D4-FF34-1F34767DEabc}"
   Const SE_VPS_NAME = "SleepBetweenSessionsWithClientIPinMilliseconds"
   Const SE_VPS_VALUE = 50
   
   Sub SetValue()
   
       ' Create the root object.
       Dim root  ' The FPCLib.FPC root object
       Set root = CreateObject("FPC.Root")
   
       'Declare the other objects needed.
       Dim oArray       ' An FPCArray object
       Dim VendorSets  ' An FPCVendorParametersSets collection
       Dim VendorSet   ' An FPCVendorParametersSet object
   
       ' Get references to the array object
       ' and the network rules collection.
       Set oArray = root.GetContainingArray
       Set VendorSets = oArray.VendorParametersSets
   
       On Error Resume Next
       Set VendorSet = VendorSets.Item( SE_VPS_GUID )
   
       If Err.Number <> 0 Then
           Err.Clear
   
           ' Add the item
           Set VendorSet = VendorSets.Add( SE_VPS_GUID )
           CheckError
           WScript.Echo "New VendorSet added... " & VendorSet.Name
   
       Else
           WScript.Echo "Existing VendorSet found... value- " &  VendorSet.Value(SE_VPS_NAME)
       End If
   
       if VendorSet.Value(SE_VPS_NAME) <> SE_VPS_VALUE Then
   
           Err.Clear
           VendorSet.Value(SE_VPS_NAME) = SE_VPS_VALUE
   
           If Err.Number <> 0 Then
               CheckError
           Else
               VendorSets.Save false, true
               CheckError
   
               If Err.Number = 0 Then
                   WScript.Echo "Done with " & SE_VPS_NAME & ", saved!"
               End If
           End If
       Else
           WScript.Echo "Done with " & SE_VPS_NAME & ", no change!"
       End If
   
   End Sub
   
   Sub CheckError()
   
       If Err.Number <> 0 Then
           WScript.Echo "An error occurred: 0x" & Hex(Err.Number) & " " & Err.Description
           Err.Clear
       End If
   
   End Sub
   
   SetValue
   

3. Save this Notepad file by using the .vbs file name extension. For example, use the following name to save this file:
   SleepBetweenSessionsWithClientIPinMilliseconds.vbs
4. Click Start, click Run, type cmd, and then click OK.
5. At the command prompt, run the following command:
   cscript SleepBetweenSessionsWithClientIPinMilliseconds.vbs

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

For more information about software update terminology, click the following article number to view the article in the Microsoft Knowledge Base: