Microsoft KB Archive/944114

= You receive an error message when you access a Web site through ISA Server 2004 that has the Compression Filter Web filter enabled =

Article ID: 944114

Article Last Modified on 12/5/2007

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APPLIES TO


 * Microsoft Internet Security and Acceleration Server 2004 Enterprise Edition
 * Microsoft Internet Security and Acceleration Server 2004 Standard Edition

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SYMPTOMS
Consider the following scenario:
 * You access a Web site that is published in Microsoft Internet Security and Acceleration (ISA) Server 2004. Or, you access a Web site by using ISA Server 2004 as the Web proxy.
 * The Compression Filter Web filter is enabled in ISA Server 2004.
 * The Web site sends an HTTP/0.9 response to the client.

In this scenario, you receive one of the following error messages.

Error message 1

HTTP/1.1 502 Proxy Error (The specified network name is no longer available.)

Error message 2

Error Code 64: Host not available

Background: The gateway or proxy server lost connection to the Web server.



CAUSE
An HTTP/0.9 response has only a body, but no headers. The Web site closes the connection to indicate the end of a response.

However, the Compression Filter Web filter in ISA Server expects an HTTP/1.0 or HTTP/1.1 response. The Compression Filter Web filter does not recognize an HTTP/0.9 response. Therefore, the Compression Filter Web filter assumes that the connection is lost or reset before the Web site can send all the HTTP response headers.



RESOLUTION
To resolve this problem, follow these steps:  Apply the hotfix package that is described in the following Microsoft Knowledge Base article:

945043 Description of the ISA Server 2004 hotfix package: November 12, 2007

 Start Notepad.  Copy the following code, and then paste it into Notepad. Const SE_VPS_GUID = &quot;{143F5698-103B-12D4-FF34-1F34767DEabc}&quot; Const SE_VPS_NAME = &quot;EnableHotfix944114&quot; Const SE_VPS_VALUE = true

Sub SetValue

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

'Declare the other required objects. Dim array      ' An FPCArray object Dim VendorSets ' An FPCVendorParametersSets collection Dim VendorSet  ' An FPCVendorParametersSet object

' Get references to the array object ' and to 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 as a Microsoft Visual Basic script file by using the .vbs file name extension. For example, use the following name to save the file:

EnableHotfix944114.vbs

 At a command prompt, change to the location where you saved the file in step 4, and then run the following command:

cscript EnableHotfix944114.vbs



Note To revert to the default setting, edit the script by changing &quot;Const SE_VPS_VALUE = true&quot; to &quot;Const SE_VPS_VALUE = false.&quot; Save the script, and then run it again.



WORKAROUND
To work around this problem, disable the Compression Filter Web filter in ISA Server.

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

Keywords: kbqfe kbexpertiseinter KB944114

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