How would you ensure that DHCP services will continue to function in the event of a failure of any single component?

The ABC.com network consists of a single Active Directory domain named ABC.com. All servers
on the ABC.com network run Windows Server 2003 Enterprise Edition and all client computers run
Windows XP Professional. ABC.com has its headquarters in Chicago and a branch office in
Dallas.
The Chicago and Dallas offices are connected by permanent leased line connection with a
hardware router at each end of the connection.
Currently all client computers in both offices receive their IP configurations from a single Windows
Server 2003 server located in the Chicago office.
You are designing a new DHCP architecture to improve the performance and reliability of the
system.

How would you ensure that DHCP services will continue to function in the event of a failure of any
single component? Choose two.

A.
Set up two Windows Server 2003 computers as a DHCP server cluster in the Chicago office.

B.
Install two Windows Server 2003 computers as a DHCP server cluster in the Dallas office.

C.
Configure a Windows Server 2003 computer at the Dallas office as a DHCP relay agent.

D.
Install a Windows Server 2003 computer as an additional DHCP server in the Dallas office.

E.
Set up a Windows Server 2003 computer at the Chicago office as a DHCP relay agent.

F.
Configure one DHCP server to handle 75 percent of the IP address scope and the other DHCP
server to handle 25 percent.

Explanation:
The best fault tolerant solution here would be to implement a DHCP server cluster in
each office.
The Windows Server 2003 DHCP Server service is a cluster-aware application, which is an
application that can run on a cluster node and that can be managed as a cluster resource. These
applications use the Cluster API to receive status and notification information from the server
cluster.
You can implement additional DHCP (or MADCAP) server reliability by deploying a DHCP server
cluster using the Cluster service. This service is the essential software component that controls all
aspects of server cluster operation and manages the cluster database. Each node in a server
cluster runs one instance of the Cluster service provided with Windows Server 2003, Enterprise
Edition. By using clustering support for DHCP, you can implement a local method of DHCP server
failover, achieving greater fault tolerance. You can also enhance fault tolerance by combining
DHCP server clustering with a remote failover configuration, such as by using a split scope
configuration.
Another way to implement DHCP remote failover is to deploy two DHCP servers in the same
network that share a split scope configuration based on the 80/20 rule.
Reference:
Craig Zacker, MCSE Self-Paced Training Kit (Exam 70-293): Planning and Maintaining a Microsoft
Windows Server 2003 Network Infrastructure, Microsoft Press, Redmond, Washington, 2004, p.
7:2