Introduction to DNS

All answers must be typed!

This section helps you understand about DNS nameserver. Please note that these questions are designed for testing on Windows machine. You may want to read the slides first.

B- Using nslookup command (nslookup ucc.edu.gh) answer the following questions: (note that if you get timeout for any of the commands, that is because your connection is intermittent; so try again!)

  1. What is the IP address for ucc.edu.gh?
  2. What is the IP address of the DNS server of ucc.edu.gh? Can you tell the name of the DNS server machine (DNS nameserver)?
  3. What is the significance of doing nslookup ucc.edu.gh 208.67.222.222
  4. What is the IP address of host resolver1.opendns.com?
  5. Where is resolver1.opendns.com machine physically located at? What is its significance? You can use Trace IP site
  6. What is the average round trip time (RTT) when you ping UCC DNS nameserver? How is it compared to pinging google.com?
  7. What is the IP address of www.ucc.edu.gh? (you can use -querytype=ns option of nslookup command. Do you remember what is -querytype=ns is used for? What is the actual host name of the web server www.ucc.edu.gh? (read about DNS Records)
  8. If you want to see how many hops are between your machine and www.ucc.edu.gh you can use traceroute (tracert in wondows) command. How many hops are between your machine and www.google.com? Make sure you know how it works!
  9. While In C:\ prompt, type nslookup. At the > prompt type >set debug. Then, type >ucc.edu.gh. When you receive the response (ANSWER) how many authoritative DNS nameservers can resolve request about TLD gh?

C- Complete the Wireshark below:

  1. Complete the Wireshark DNS Example and answer all the questions.
  2. Download dns_simple_query if needed

Extra: If you like to learn more (Do not turn this part in)

Answer the following questions:

  1. How many DNS root-servers exist around the globe? You can use http://public-root.com/root-server-check/index.htm
  2. What is the difference between ccTLD and gTLD? Give an example for each.
  3. What command will you use to find out the host name for IP address 207.46.249.222?
  4. Does dig command work on Windows machines?
  5. Read the information on this link: http://help.slamdot.com/idx/0/057/What-are-the-types-of-DNS-records. What is the purpose of NS and A records?
  6. What is FQDN?
  7. Which port is dedicated to DNS application?
  8. What are DNS common software?

More Extra Questions:

  1. Read Part I of the DNS exercise. Complete part II and answer all the questions. You can obtain a trail version of VisualRoute. You can also use traceroute command.
  2. As for routing this is an easy tutorial on Netstat.

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