DHCP Server Migration Made Easy in Windows Server 2008

If you have ever had to move a DHCP Server from one physical server to another, you know that the process isn’t exactly fun or intuitive if the servers are running Windows Server 2003. Fortunately, when Microsoft created Windows Server 2008, they completely redesigned the administrative interface, and in doing so, also made DHCP much easier to migrate. In this article, I will show you how it’s done.

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Migration in Windows Server 2003

Since this article is supposed to be about Windows Server 2008, I don’t want to talk too much about Windows Server 2003. Even so, I do want to give you a quick overview of the migration process that was used in that version of Windows so that you can better appreciate what I am about to show you.

To migrate a Windows 2003 DHCP Server, the first thing that you must do is to stop, and then disable the DHCP service. Of course this means that clients will not be able to use the DHCP server to obtain IP addresses until the process is complete.  You must then copy the server’s \%systemroot%\system32\DHCP folder to a safe location that you can use later on. After doing so, you should remove this folder from the original server.

Next, you will have to do some work through the Registry Editor. As always, when you are working with the Registry Editor, you should make a backup first, because making an incorrect change can destroy Windows. With that said, navigate through the Registry Editor to HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\DHCPServer\Configuration. Now, choose the Save Key command from the editor’s Registry menu, and export the registry key to a safe location. When you are done, you can uninstall the Add / Remove Windows Components Wizard to uninstall the DHCP server component.

Restoring a DHCP Server Backup in Windows Server 2003

Before you can restore your DHCP server backup, you must install the DHCP server component onto the new server, but after doing so, you must stop and temporarily disable the DHCP service. Now, check the backup directory that you created earlier for a file named system.mdb. If this file exists, rename it to system.src. You may now copy all of the files from the backup directory to the new server’s %systemroot%\system32\DHCP folder.

Now you have to restore the backup copy of the registry that you created earlier. To do so, open the Registry Editor and navigate through the registry tree to HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\DHCPServer\Configuration. Choose the Restore command from the editor’s Registry menu, and then restore the registry backup file that you created earlier.  When you are done, close the Registry Editor, reboot the machine, and then enable and start the DHCP service.

Migration in Windows Server 2008

As you can see, moving the DHCP service from one server to another in Windows Server 2003 was a real pain. Fortunately, the process is a lot easier in Windows Server 2008. Begin the process by opening the DHCP Manager, found on the server’s Administrative Tools menu. When the console opens, right click on the server name, and then choose the Backup command from the resulting shortcut menu, as shown in Figure A.

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Figure A Right click on the server’s name, and choose the Backup command from the resulting shortcut menu.

When you do, Windows will prompt you to enter a location for the backup file that you are creating. After entering a location, click OK, and the backup file will be created.

Restoring a DHCP Backup in Windows Server 2008

Microsoft makes restoring a backup just as easy. To do so, just open the DHCP management console, right click on the server that you want to restore the backup to, and choose the Restore command from the resulting shortcut menu. You can see the Restore option shown in Figure A. Now, just specify the location of the backup that you want to restore, and click OK. Windows will now ask you if it is OK to stop and restart the DHCP Server service, as shown in Figure B. Click Yes, and the restore will begin. When the process completes, the DHCP Server service should automatically restart with the new settings.

Figure B You must restart the DHCP Server service in order for the restore operation to work correctly.

Note:

One of my readers - Mike Pagan - has identified some issues with this procedure and pointed me to an interesting Microsoft KB article:

"I was following along with this article and the DHCP scope appeared to migrate properly, but I had some issues.  The reservations were blank and the active leases would not pull up and displayed a red X on the category. I did some further checking and found this article at Microsoft’s support site: http://support.microsoft.com/kb/962355.  I followed this article and I was able to migrate all the settings including the reservations and active leases."

Thanks Mike!

Conclusion

In this article, I have shown you how to migrate a DHCP Server configuration from one server to another. Keep in mind that regardless of whether you are performing this procedure in Windows Server 2003 or Windows Server 2008, you must disable any DHCP server that contains a conflicting scope prior to performing a restoration.