You are a network administrator for your company. The network consists of a single Active Directory domain. All domain controllers and member servers run Windows Server 2003, Enterprise Edition. All client computers run Windows XP Professional. The company has one main office and one branch office.

The two offices are connected by a T1 WAN connection. There is a hardware router at each end of the connection. The main office contains 10,000 client computers, and the branch office contains 5,000 client computers. You need to use DHCP to provide IP addresses to the Windows XP Professional computers in both offices.

You need to minimize network configuration traffic on the WAN connection. Your solution needs to prevent any component involved in the DHCP architecture from becoming a single point of failure.

What should you do?

A.
At the main office, configure two Windows Server 2003 computers as a DHCP server cluster. At the branch office, configure two Windows Server 2003 computers as a DHCP server cluster.

B.
At the main office, configure two Windows Server 2003 computers as a DHCP server cluster. At the branch office, configure a Windows Server 2003 computer as a DHCP relay agent.

C.
At the main office, configure two Windows Server 2003 computers as DHCP servers. Configure one DHCP server to handle 80 percent of the IP address scope and the other DHCP server to handle 20 percent. Configure the branch office router as a DHCP relay agent.

D.
At the main office, configure two Windows Server 2003 computers as a DHCP server cluster. Configure the branch office router as a DHCP relay agent.

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.

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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.
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