DhcpExim in Action

While researching this article, I encountered several methods for transferring DHCP server configuration and scope data between various combinations of servers (e.g., Windows NT 4.0 to Windows 2000, Win2K to Win2K, Win2K to NT 4.0). These procedures are somewhat tedious and complex, and they differ slightly. Then, I discovered a much better method for transferring DHCP server configurations between machines—the fairly new and unknown DHCP Export Import (DhcpExim) utility, which works with any combination of Win2K and NT 4.0 systems. I stumbled upon a reference to this utility in a Microsoft article, which stated that the utility is part of Microsoft Windows 2000 Server Resource Kit Supplement One. I didn't yet have my copy of this update, so I figured I'd just download DhcpExim from the Microsoft Web site. Unfortunately, Microsoft doesn't make this utility available for download. Not one to give up easily, I found DhcpExim at ftp://ftp.mddinc.com/microsoft. Be sure to grab both dhcpexim.exe and its companion readme file, dhcpexim_readme.txt. (I subsequently obtained Supplement One, and it doesn't list DhcpExim as included on the CD-ROM.)

Using DhcpExim is a dream, especially when you contrast it with the alternative procedures for backing up and restoring or migrating DHCP configurations between servers. The first step is to export the DHCP configuration from the source server. The configuration data includes general server configuration information and the scopes you specify for export. I found the scope granularity to be an especially welcome feature.

To export a server's DHCP configuration, run dhcpexim.exe, and in the first step of the wizard, select the Export configuration of the local service to a file option. Next, name the saved configuration file. Finally, select the scopes you want to export, as Figure A shows, and click Export. To import a saved configuration, you select the utility's Import configuration to the local service from a file option and locate the file that contains the saved configuration.

I recommend running DhcpExim on all your DHCP servers and maintaining the resulting configuration export files in a safe place. In addition, consider regularly updating these configuration export files.