For starters, Microsoft has decided to disable network mapping for any workstation connected to a domain network. The other problem is that even if you enable the network-mapping feature, it will map only computers running Windows Vista and Windows Server 2008. The mapping software will also detect Xboxes, switches, routers and various related networking hardware, but it won't map machines that are running older versions of Windows. As you can see in Figure A, machines that are running older versions are displayed, but they are displayed at the bottom of the window, outside of the map.
Machines running older versions of Windows are displayed outside of the map. (Click image to view larger.)
Fortunately, there is a way of fixing both of these problems. We have already seen in Figure A that it is possible to enable network mapping in a domain environment. Doing so is actually pretty simple. You just need to adjust a couple of group policy settings.
1. Open a Command Prompt window, and enter the GPEDIT.MSC command. Doing this will open the Group Policy Object Editor. The machine's local security policy will be loaded by default.
2. Navigate through the group policy hierarchy to Local Computer Policy | Computer Configuration | Administrative Templates | Network | Link Layer Topology Discovery. When you select the Link Layer Topology Discovery container, the Details pane will display two group policy settings, as shown in Figure B.
3. At this point, you must enable the Turn on I/O (LLTDK) Driver setting. When you do, the setting's properties sheet will contain several check boxes. You must select the Allow Operation While in Domain check box, as shown in Figure C. For security reasons, you should not enable mapping when attached to a public network.
You must allow mapping while in a domain.
4. The next setting allows you to turn on the responder driver. This allows the machine to be detected for placement on a network map. Again, you should enable this setting, but you should allow the responder to operate only on a domain network.
5. You should now be able to view a map of your network. If other machines running Windows Vista do not show up on the map, it is usually because the responder is not enabled on those machines.
6. Our next task is to turn our attention to machines that are running an older version of Windows. The good news is that Microsoft has released an update for Windows XP that will allow those machines to be included in a Windows Vista network map. You can download the necessary driver on Microsoft's support page for this issue, "Network map in Windows Vista does not display computers that are running Windows XP.
The driver that is available for download at the link above is a Link Layer Topology Discovery Responder, similar to the one used by Windows Vista. Installing the driver is surprisingly simple. All you have to do is visit the website, validate your copy of Windows, and then download the file. The file itself is less than half a megabyte in size, and the installation process is super-simple. When the Setup wizard completes, the machine will be visible to Vista's network map, but you will have to press the F5 key to refresh the map.
7. If you look at Figure D, you will notice that my laptop, named "Brick" (because of its weight when I travel), is linked to my network via a wireless connection. If you go back to Figure A, you can see that the same machine was listed at the bottom of the diagram with all of the other machines that are running Windows XP and Windows Server 2003.
Unfortunately, Microsoft does not make an LLTD driver for Windows Server 2003 and reportedly has no plans to create one. Out of curiosity, I tried installing the Windows XP version onto a machine that was running Windows Server 2003, but I couldn't get it to install.
About the author:
Brien M. Posey, MCSE, is a Microsoft Most Valuable Professional for his work with Windows 2000 Server and IIS. Brien has served as CIO for a nationwide chain of hospitals and was once in charge of IT security for Fort Knox. As a freelance technical writer, he has written for Microsoft, CNET, ZDNet, TechTarget, MSD2D, Relevant Technologies and other technology companies. You can visit Brien's personal website at www.brienposey.com.
This was first published in May 2008