The Best and simplest way to export and import DHCP setting between servers is with NETSH utility, For example to export all the DHCP settins, First open CMD as Administrator on the server with the dhcp running :
netsh dhcp server \\localhost export c:\dhcp-settings all
Then copy the file c:\dhcp-settings to the new server (in this example to c:\), Add the DHCP Role and then open CMD as Administrator:
netsh dhcp server \\localhost import c:\dhcp-settings
Restart the DHCP server service just to be on the safe side that all is well and check if the setting migrated fully .
Another example – The following command exports the configuration that pertains to scopes 10.0.0.0 and 20.0.0.0 to the c:\Temp\Dhcpdb file:
export c:\temp\dhcpdb 10.0.0.0 20.0.0.0
And to import back to the new server :
import c:\temp\dhcpdb 10.0.0.0 20.0.0.0
More inforamtion can be found here