A - Install the DHCP role on the WS08 server (do not authorise DHCP at this point)
B - Stop the DHCP service on the WS03 server after export and before authorising the new DHCP server
1. Export DHCP database from the source WS03 server using cmd:
netsh dhcp server export C:\dhcpdatabase.dat all
2. On the WS08 server, copy the exported DHCP file to the C:\ directory
3. Run the below using an administrator cmd:
netsh dhcp server import c:\dhcpdatabase.dat all
4. Review all configurations to confirm everything has been imported correctly (see note B above)
5. Authorise the WS08 server DHCP service, a green arrow will appear when successful.
6. Test new DHCP server eg start up DHCP clients and confirm IP's are being provided.
7. After testing has been completed, on the WS03 DHCP server either disable the DHCP server service, uninstall the DHCP role or shutdown the server.
Choose the option which suits best, but remember you must never have two active DHCP servers on the same subnet.
A known issue sometimes occurs where the leased address data does not appear after the import has completed. Fortunately this has been acknowledges by Microsoft and there is a solution which pretty much boils down stopping the DHCP service, deleting the DHCP database and starting the DHCP service on the new WS08 server before the import (ie after step 2 above)
For more information on this workaround refer to this article- http://blogs.technet.com/b/teamdhcp/archive/2009/02/18/migration-of-dhcp-server-from-windows-server-2003-to-windows-server-2008.aspx
* WS03 = Windows Server 2003
* WS08 = Windows Server 2008