Microsoft KB Archive/937841

= ISA Server 2006 forwards requests to an incorrect Web server when a client computer accesses Web sites that have different URLs in the same session =

Article ID: 937841

Article Last Modified on 8/14/2007

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APPLIES TO


 * Microsoft Internet Security and Acceleration Server 2006 Standard Edition
 * Microsoft Internet Security and Acceleration Server 2006 Enterprise Edition

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SYMPTOMS
Consider the following scenario:
 * In Microsoft Internet Security and Acceleration (ISA) Server 2006, you create a Web farm that contains multiple Web servers.
 * You create multiple Web publishing rules to publish multiple Web sites by using this Web farm.
 * In the Web publishing rules, the load balance mechanism is set to Cookie based.

In this scenario, ISA Server forwards requests to an incorrect Web server. When a client computer accesses Web sites that have different URLs in the same session, ISA Server does not forward the requests to the same Web server.

For example, this problem occurs when the client computer accesses the following Web sites in the same session:
 * http:// /Site1
 * http:// /Site2



CAUSE
This problem occurs because ISA Server implements load balancing based on specific policy rules. If all requests from a client session are enabled by the same policy rule, they reach the same Web server. However, if requests are enabled by different policy rules, requests from the same session may reach different Web servers.



RESOLUTION
 Apply hotfix 940250. For more information about this hotfix, click the following article number to view the article in the Microsoft Knowledge Base:

940250 Description of the ISA Server 2006 hotfix package: July 16, 2007

  Start Notepad, and then paste the following script into a new document. Const SE_VPS_GUID = &quot;{143F5698-103B-12D4-FF34-1F34767DEabc}&quot; Const SE_VPS_NAME = &quot;EnableHotfix937841&quot; Const SE_VPS_VALUE = true

Sub SetValue

' Create the root obect. Dim root ' The FPCLib.FPC root object Set root = CreateObject(&quot;FPC.Root&quot;)

'Declare the other objects needed. Dim array      ' 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 array = root.GetContainingArray Set VendorSets = array.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 &quot;New VendorSet added... &quot; & VendorSet.Name

Else WScript.Echo &quot;Existing VendorSet found... value- &quot; & 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 &quot;Done with &quot; & SE_VPS_NAME & &quot;, saved!&quot; End If       End If    Else WScript.Echo &quot;Done with &quot; & SE_VPS_NAME & &quot;, no change!&quot; End If

End Sub

Sub CheckError

If Err.Number <> 0 Then WScript.Echo &quot;An error occurred: 0x&quot; & Hex(Err.Number) & &quot; &quot; & Err.Description Err.Clear End If

End Sub

SetValue  Save the file by using the .vbs file name extension. For example, use the following name to save the file:

EnableKB937841.vbs

Note Microsoft Visual Basic script files use the .vbs file name extension. At a command prompt, move to the location where you saved the .vbs file, type the following command, and then press ENTER:

cscript EnableKB937841.vbs





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
For more information about a similar problem, click the following article number to view the article in the Microsoft Knowledge Base:

940242 ISA Server 2006 forwards requests to an incorrect Web server when a client computer accesses Web sites that have different host names in the same session

Keywords: kbtshoot kbexpertiseinter kbprb KB937841

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