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

View products that this article applies to.

Expand all | Collapse all

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.

Back to the top

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.

Back to the top

RESOLUTION

To resolve this problem, follow these steps:

Apply the hotfix package that is described in the following Microsoft Knowledge Base article:
945043 (http://support.microsoft.com/kb/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 = "{143F5698-103B-12D4-FF34-1F34767DEabc}"
Const SE_VPS_NAME = "EnableHotfix944114"
Const SE_VPS_VALUE = true

Sub SetValue()

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

    '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 "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

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 "Const SE_VPS_VALUE = true" to "Const SE_VPS_VALUE = false." Save the script, and then run it again.

Back to the top