NSLOOKUP questions
In this section, you are going to use your own computer to do some direct querying of DNS servers. To start, use Google to determine the locations to lookup. On a Windows computer, open a command prompt on your personal machine by going to start/run and typing CMD then pressing Enter. For a Mac, use the 'Terminal' application in Macintosh HD->Applications->Utilities->Terminal. Once you have the command line open, you can issue nslookup commands simply by typing them in at the command line.
- Run nslookup to obtain the IP address of some web server of your choosing. Make sure to report the web server's IPv4 address, not the IP address of the DNS server that responded to your request. Paste a screen shot of the results into your report to supplement your answer.
- Make an nslookup query for a university in Europe to find its "authoritative" DNS servers. (hint, execute the nslookup command with the -type=NS option on just the last two parts of the named address - like nslookup -type=NS www.sjsu.edu
- ) Paste a screen shot of the results into your report to supplement your answer.
- Make an nslookup query using your primary DNS and an alternate server for mail.yahoo.com. Since most organizations now restrict their DNS servers to internal use only, try one of the open DNS services listed on this Free and Public DNS Servers List
- (Links to an external site.)
- Links to an external site.
- . Compare the results you get when querying the address for mail.yahoo.com on a DNS server from the United States vs. one from Europe or Asia. Provide a screen shot of your results. Why do you think you might get different results from different parts of the world?
- Hint: the command looks like nslookup mail.yahoo.com xxx.xxx.xxx.xxx where the xx's are the named address or IP address of some other DNS Server.