KB ID 0000447 Dtd 18/05/11
Normally you can just create a new scope on your new DHCP server, but if you have a lot of reservations that you don't want to have to recreate (for printers network devices etc), then it's a better option to migrate/copy the scope to the new server.
1. Copy all the DHCP settings to a text file with the following command;
netsh dhcp server export C:\dhcp.txt all
2. Stop and disable the DHCP Server service on the OLD DHCP server.
3. Move the text file to the NEW server, and import the settings with the following command;
netsh dhcp server import c:\dhcp.txt all