Article ID: 934410 - Last Review: April 16, 2007 - Revision: 1.2

Disruption of service to all remote sites and high CPU utilization by Lsass.exe and Netsh.exe processes in IPsec tunnel mode site-to-site VPN scenario in ISA Server 2006

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SYMPTOMS

You configure many IPsec tunnel mode site-to-site virtual private network (VPN) connections on a computer that is running Microsoft Internet Security and Acceleration (ISA) Server 2006. When you update the VPN configuration, you notice sustained high CPU utilization by the following processes:

Lsass.exe
Netsh.exe

The high CPU utilization decreases after a certain time, depending on the number of site-to-site VPN connections.

Additionally, you experience the following symptoms:

All remote sites lose connectivity.
There is disruption of ISA services, such as server publishing rules.
When you stop the firewall service, you receive an error message that states that the service cannot be stopped.

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CAUSE

This problem occurs because ISA server deletes and then re-creates all the IPsec filters when you reload the VPN configuration.

ISA server creates a mesh topology of IPsec filters to allow for traffic between all the sites and the ISA server. This process occurs even if no network rules are configured to enable the traffic between all the sites and the ISA server. When you update a VPN configuration, ISA server deletes and then re-creates all the IPsec filters. If you have many sites, it takes a long time for the ISA server to delete and then to re-create the IPsec filters.

Note You can use IPsec Policy Microsoft Management Console (MMC) snap-in to view IPsec filters.

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RESOLUTION

To resolve this problem, install the hotfix that is described in Microsoft Knowledge Base article 934587.

934587 (http://support.microsoft.com/kb/934587/ ) Description of the ISA Server 2006 hotfix package: March 30, 2007

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Post-hotfix installation information

After you install the hotfix, you must run the following Microsoft Visual Basic script. To do this, follow these steps:

Start Notepad.

Copy the following script into a Notepad file, and then save the text file as a Visual Basic script file by using the .vbs file name extension. For example, save the file as HotfixKB934410.vbs.

Const SE_VPS_GUID = "{143F5698-103B-12D4-FF34-1F34767DEabc}"
Const SE_VPS_NAME = "EnableHotfix934410"
Const SE_VPS_VALUE = true

Sub SetValue()

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

    '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 "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

Double-click the Visual Basic script file that you created in step 2 to run the script.

To remove the script, you must run the following Visual Basic script.

Const SE_VPS_GUID = "{143F5698-103B-12D4-FF34-1F34767DEabc}"
Const SE_VPS_NAME = "EnableHotfix934410"
Const SE_VPS_VALUE = false

Sub SetValue()

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

    '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 "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

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