i have 2 Servers acting as the AD and DHCP server, both are in different locations but both are on the same Domain Name.

if one is running 192.168.0.0 and the other is 192.168.13.0

can the DHCP Server inside the 13.0 issue ip to the 0.0 Network. 

if i create a Fail over  ?

Hi Dave,

We could use DHCP relay agent to achieve the goal.

When clients are sending DHCP packets, the relay agent would forward the packets to the DHCP server. And forward the packets sent by DHCP server to clients.

Here is the guide of DHCP relay agent:"
DHCP Relay Agent:
https://technet.microsoft.com/en-us/library/cc783103%28v=ws.10%29.aspx?f=255&MSPPError=-2147217396

Configure the DHCP Relay Agent:
https://technet.microsoft.com/en-us/library/cc781416(v=ws.10).aspx

DHCP failover in Server 2012 is a new feature that enables two DHCP servers to share service availability information with each other, providing DHCP high availability.
Here is the reference:
Understand and Deploy DHCP Failover:
https://technet.microsoft.com/en-us/library/dn338978.aspx

Best Regards,

Leo