Welcome to Certifiable, your exam prep headquarters. Here you'll find questions about some of the tricky areas that are fair game for the certification exams. Following the questions, you'll find the correct answers and explanatory text. We change the questions weekly.

Questions (June 1, 2001)
Answers (June 1, 2001)

Questions (June 1, 2001)

Question 1
You're creating a subnet that will start out with 836 hosts and grow 10 percent a year for the next 5 years. How many bits must be in your subnet mask to support the number of hosts expected on the subnet in 5 years?

  1. 8
  2. 16
  3. 21
  4. 22
  5. 24

Question 2
Which TCP/IP service translates a NetBIOS computer name into an IP address?

  1. DNS
  2. WINS
  3. DHCP
  4. ARP

Question 3
Which Resource Record (RR) type in Windows 2000 enables integration of Active Directory (AD) and DNS?

  1. A
  2. PTR
  3. SRV
  4. in.addr.arpa

Answers (June 1, 2001)

Answer to Question 1
The correct answer is C—21. The subnet mask indicates which bits in an IP address identify the network and which bits identify the host ID. Divided into two parts, the leftmost bits of the subnet mask indicate the network address and the rightmost bits indicate the host ID. Because the maximum number of hosts must be a power of 2, more than 1300 hosts will require the host address part of the subnet mask to consist of 11 zeroes (2 to the power of 10 is 1024, and 2 to the power of 11 is 2048). The remaining bits indicate the network address; therefore, the subnet mask should be 21 bits (i.e., 32 – 11). For example, the notation for a network using a private TCP/IP address range would be 192.168.0.0/21.

Answer to Question 2
The correct answer is B—WINS. When Microsoft added networking support to Windows, the developers used alphanumeric names based on the NetBIOS API for each computer on the network. Windows NT, Windows Me, and Windows 9x still use NetBIOS names to identify computers, domains, and browser lists, while Windows 2000 supports NetBIOS naming for backward compatibility. WINS maintains a list of NetBIOS names and their corresponding IP addresses and lets clients translate a NetBIOS name to its IP address on a network with multiple subnets.

Answer to Question 3
The correct answer is C—SRV. Service Resource Records (SRV RRs) in DNS let DNS locate Active Directory (AD) domain controllers (DCs). DNS services in Windows 2000 support three types of zones: standard primary, standard secondary, and Active Directory integrated. A standard primary zone is the authoritative source for DNS information. A standard secondary zone is a copy (or replica) of the master database and is read-only. An Active Directory integrated zone is a zone that is stored in AD and is replicated during AD replication.

Two events trigger zone transfers in DNS: a master server sends a change notification to the secondary servers, or a secondary server queries the master for changes in the master database. Win2K includes in DNS the ability to accept dynamic updates rather than just manual updates to the zone database.