To resolve this problem, follow these steps:
- Apply the hotfix package that is described in the following Microsoft Knowledge Base article:
945225�
                             Description of the ISA Server 2006 hotfix package: November 18, 2007
  - Start Notepad.
 - Copy and then paste the following text into Notepad.
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. ' -+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-
' -+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-
'    This code is Copyright (c) 2007 Microsoft Corporation.  
'
'    All rights reserved.
'
'    THIS CODE AND INFORMATION IS PROVIDED "AS IS" WITHOUT WARRANTY OF
'    ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING BUT NOT LIMITED TO
'    THE IMPLIED WARRANTIES OF MERCHANTABILITY AND/OR FITNESS FOR A
'    PARTICULAR PURPOSE.
'
'    IN NO EVENT SHALL MICROSOFT AND/OR ITS RESPECTIVE SUPPLIERS BE
'    LIABLE FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY
'    DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS,
'    WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
'    ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE
'    OF THIS CODE OR INFORMATION.
'
' -+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-
Const SE_VPS_GUID = "{143F5698-103B-12D4-FF34-1F34767DEabc}"
Const SE_VPS_NAME = "CreateDomainCookie"
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
        SetWPLBhttpOnly args(0)
    Else
        Usage()
    End If
End Sub
Sub SetWPLBhttpOnly(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
 - Save the file as a .vbs file. For example, use the following name to save the file:
CreateDomainCookie.vbs
 - Open a command prompt, move to the location in which you saved the CreateDomainCookie.vbs file, and then type the following command:
cscript CreateDomainCookie.vbs Rulename
Note Replace the Rulename placeholder with the name of the publishing rule. 
After you follow these steps, ISA Server checks the top-level domain from the host header in the request. Then, ISA Server uses this domain as a WPLB cookie domain. For example, if the requested host header is test.xxx.domain.com, the cookie will be "cookie domain: .domain.com."
Note When ISA Server obtains the top-level domain, ISA Server merely extracts the rightmost two names. For example, if the site name is 
a.
b.
c.
d.com, ISA Server uses .
d.com as the top-level domain in the WPLB cookie. Therefore, this fix does not help you if your top-level domain resembles "
domain.co.uk" or if you want to use 
c.
d.com as the top-level domain. In this case, you can use another fix to specify a single top-level domain that can be used in all WPLB cookies. 
For more information, 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