Domain Name Service Basics - Quiz Explanation

The answers you selected are indicated below, along with text that explains the correct answers.
 
1. What is the function of a top-level domain name?
Please select the best answer.
  A. To designate all hosts belonging to organizations of particular types
  B. To divide the DNS namespace among organizations with networks
  C. To manage the relationship between the DNS namespace and IP addresses
  D. To subdivide domain names into additional names for departments and divisions
  The correct answer is A. The top-level domain names currently used most often are com, edu, gov, mil, org, net, and int, along with country codes for individual countries.

2. What is a reverse lookup?
Please select the best answer.
  A. A way to find a host’s numeric IP address by using the host’s name
  B. A way to replace a host’s numeric IP address with a host name
  C. A way to find a host’s name by using that host’s numeric IP address
  D. A way to subdivide a domain name into additional names
  The correct answer is C. The DNS system can convert IP addresses into names by associating a domain name with a network address.

3. How is the DNS namespace organized?
Please select the best answer.
  A. Into numeric IP addresses and host names
  B. Into paths from the root to a DNS entity
  C. Into a tree of domains and subdomains
  D. Into absolute path names of files in the UNIX system
  The correct answer is C. A DNS entity’s name is specified by its position in this tree of domains and subdomains, each subdomain name separated from the next by a period (“dot”).