ExamSim MCSE 2000: Design A Dynamic DNS Network Page 2
This question is typical of the Microsoft exam questions that you'll see on the actual test. The exam questions will not fit in a nice format where you will be tested on one concept at a time. And indeed, this question is actually testing your knowledge of multiple concepts. In this case, you need to have a decent understanding of Dynamic DNS and DHCP in Windows 2000.
Answer D is correct because we need fault tolerance for DNS record registration. Only two types of DNS Servers can receive and update DNS records: An Active Directory integrated DNS Server and a Standard Primary DNS Server. Note that the Active Directory integrated DNS Servers all act as Primaries for their domain. DNS Clients can send their DNS registration information to a Secondary DNS Server, but the Secondary DNS Server must forward this information to a Primary DNS Server in order to have it updated in the Dynamic DNS zone database. Therefore, a fault tolerant Dynamic DNS registration architecture will include more than one Primary for the domain. The only was to accomplish this is to use Active Directory integrated zones. Standard DNS zones only allow for a single Primary DNS zone database file.
Its important that the clients are configured with the IP addresses of all the DNS Servers on the network, so that in the event that one of them becomes unavailable, the client can register with, and query an alternate DNS Server. The DNS client service will attempt to contact each DNS Server on the client's list of DNS Servers.
The second problem that must be addressed in this question is related to the downlevel clients on the network. Win 3.x, Win9x and Windows NT 4.0 clients cannot communicate with a Windows 2000 Dynamic DNS Server in order to register their IP addressing information. These downlevel client can query the Windows 2000 Dynamic DNS Server, they just cannot send their registration information themselves.
To solve this problem, you need to implement DHCP on the network. A DHCP Server can be configured to act as a "proxy" between the downlevel clients and the DDNS Server. To have the DHCP perform this function, you must configure it as in the figure below.
The Enable updates for DNS clients that do not support dynamic update checkbox must be checked if you want the DNS Server to update both the Host (A) and Pointer (PTR) information for the downlevel client in the Dynamic DNS zone database.
After the DHCP Server has been placed on the network and configured to forward IP addressing to the DDNS Server, all the downlevel network clients will have their information automatically entered into the Dynamic DNS database.
Now, let's look at the problems with the other answers.