Consider the following scenario. You publish an Outlook Web Access (OWA) Web site in Microsoft Internet Security and Acceleration (ISA) Server 2004. In the OWA Web publishing rule, you enable the
Block responses containing Windows executable content option in the HTTP filter settings. However, OWA users cannot download compressed (.zip) file attachments.
When this problem occurs, OWA users receive the following error message in the Web browser:
Technical Information (for support personnel)
Error Code: 500 Internal Server Error. The request was rejected by the HTTP filter. Contact your ISA Server administrator. (12217)
This problem occurs because OWA uses a "Content-Encoding: none" header when OWA sends compressed (.zip) file attachments. This content-encoding header indicates that the content is not encoded. However, ISA Server does not recognize this non-standard encoding schema. Therefore, ISA Server blocks the response when ISA Server inspects the response body.
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/
)
getKB -Description of the ISA Server 2004 hotfix package: date
- Start Notepad.
- Copy the following code, and then paste it into Notepad.
''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''
'
' Copyright (c) Microsoft Corporation. All rights reserved.
' THIS CODE IS MADE AVAILABLE AS IS, WITHOUT WARRANTY OF ANY KIND. THE ENTIRE
' RISK OF THE USE OR THE RESULTS FROM THE USE OF THIS CODE REMAINS WITH THE
' USER. USE AND REDISTRIBUTION OF THIS CODE, WITH OR WITHOUT MODIFICATION, IS
' HEREBY PERMITTED.
''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''
''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''
' This script sets whether ISA will treat the 'Content-Encoding: none' response header
' to mean that the content is not encoded for a specified rule
'
' usage - to enable this functionality run the script as follows:-
' cscript AllowNoneEncoding.vbs rulename
'
' where rulename is the name of the OWA Web pubishing rule
'
''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''
Const SE_VPS_GUID = "{143F5698-103B-12D4-FF34-1F34767DEabc}"
Const SE_VPS_NAME = "AllowNoneEncoding"
Const SE_VPS_VALUE = true
'Define the constants needed
const Error_FileNotFound = &H80070002
Const fpcPolicyWebPublishing = 2
Main(WScript.Arguments)
Sub Main(args)
If(args.Count = 1) Then
SetAllowNoneEncoding args(0)
Else
Usage()
End If
End Sub
Sub SetAllowNoneEncoding(ruleName)
' Create the root object.
Dim root ' The FPCLib.FPC root object
Set root = CreateObject("FPC.Root")
' Declare the other objects needed.
Dim isaArray ' An FPCArray object
Dim rule ' An FPCPolicyRule object
' Obtain a reference to the array object.
Set isaArray = root.GetContainingArray()
' Obtain a reference to the policy rule specified.
On Error Resume Next
Set rule = isaArray.ArrayPolicy.PolicyRules.Item(ruleName)
If Err.Number = Error_FileNotFound Then
WScript.Echo "The policy rule specified could not be found."
Else
Err.Clear
On Error GoTo 0
If rule.Type = fpcPolicyWebPublishing Then
Dim VendorSets ' An FPCVendorParametersSets collection
Dim VendorSet ' An FPCVendorParametersSet object
Set VendorSets = rule.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
End If
End If
rule.Save
WScript.Echo "Done!"
Else
WScript.Echo "The policy rule specified is not a Web publishing rule."
End If
End If
End Sub
Sub Usage()
WScript.Echo "Usage:" & VbCrLf _
& " " & WScript.ScriptName & " RuleName" & VbCrLf _
& "" & VbCrLf _
& " RuleName - Name of the Web publishing rule"
WScript.Quit
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
Microsoft provides programming examples for illustration only, without warranty either expressed or implied. This includes, but is not limited to, the implied warranties of merchantability or fitness for a particular purpose. This article assumes that you are familiar with the programming language that is being demonstrated and with the tools that are used to create and to debug procedures. Microsoft support engineers can help explain the functionality of a particular procedure. However, they will not modify these examples to provide added functionality or construct procedures to meet your specific requirements. - 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:
AllowNoneEncoding.vbs
- At a command prompt, change to the location where you saved the file in step 4, and then run the following command:
cscript AllowNoneEncoding.vbs Rulename
In this command, the Rulename placeholder represents the name of the OWA Web Publishing rule.
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.
To work around this problem, disable the
Block responses containing Windows executable content option in the OWA Web publishing rule.
For more information, visit the following Microsoft TechNet Web site:
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:
824684
(http://support.microsoft.com/kb/824684/
)
Description of the standard terminology that is used to describe Microsoft software updates