You experience slow Web browsing performance on internal client computers that use Internet Security and Acceleration Server or Windows Essential Business Server 2008 to manage Web requests

You may experience slow Web browsing performance on internal client computers when the following network conditions exist:

• You have an internal Domain Name System (DNS) server that cannot resolve external DNS names.
• You have internal client computers that connect to a server that is running Microsoft Internet Security and Acceleration Server (ISA Server) or Windows Essential Business Server 2008. This ISA server or Windows Essential Business Server server is configured as a firewall between the internal network and the Internet.

This problem occurs because the internal DNS server cannot resolve external DNS names for the Web request that the ISA server the Windows Essential Business Server server is requesting.

When the ISA server or the Windows Essential Business Server server receives a Web request from a client computer, the ISA server or the Windows Essential Business Server server tries to resolve the name of the requested Web site to an IP address. However, because the internal DNS server cannot resolve external DNS names, the request may take longer to process.

Note This problem may occur even if you have configured a routing rule in ISA Server or in Windows Essential Business Server.

To automatically run a Microsoft Visual Basic script that will allow the internal DNS server to resolve external DNS names, click the button in the Fix it for me section. To resolve the problem yourself by running the script included in this article, go to the Let me fix it myself section.

Fix it for me

Let me fix it myself

To resolve this problem yourself, use the Microsoft Visual Basic Scripting Edition (VBScript) code in this section to disable name resolution for the ISA Server routing rules or the Windows Essential Business Server routing rules. To run this code, follow these steps.

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, but they will not modify these examples to provide added functionality or construct procedures to meet your specific requirements.

1. Start Notepad, and then paste the following VBScript code in Notepad:

   ' 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 webProxy    ' An FPCWebProxy object 
   Dim restartMask ' A 32-bit bitmask of type FpcServices 
   
   ' Get references to the array object 
   ' and the Web proxy object. 
   
   Set isaArray = root.GetContainingArray() 
   Set webProxy = isaArray.ArrayPolicy.WebProxy 
   
   ' Configure the Web proxy to skip name resolution 
   ' while checking access and routing rules and save 
   ' the new configuration. 
   
   webProxy.SkipNameResolutionForAccessAndRoutingRules = True 
   restartMask = webProxy.GetServiceRestartMask 
   webProxy.Save 
   
   ' Restart the Firewall service so that 
   ' the change will take effect. 
   
   isaArray.RestartServices restartMask 
   WScript.Echo "Done!"
   

2. Click Save on the File menu, and then follow these steps in the Save As dialog box:
   1. In the Save as type list, click All Files.
   2. In the File name box, type FileName.vbs.
3. Copy the .vbs file to the ISA server or to the Windows Essential Business Server server, and then double-click the .vbs file to run the VBScript code.
4. Click OK when you are prompted.

Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.

For more information about Microsoft Internet Security and Acceleration Server, visit the following Microsoft Web site: For additional information about related topics, click the following article number to view the article in the Microsoft Knowledge Base: