If you receive the following error message when you are trying to create a conditional forwarders domain.
“conditional forwarding is not available because this server is a downlevel server”
This is most likely you are running at Windows 2000 DNS server. Windows 2000 DNS server does not support conditional forwarding. It only allow total forwarding.
For conditional forwarding capability, you will need to create a Windows 2003 DNS server.
Hope this help.