As usual, keep a log in the file lab8.txt of what you do in the lab so that you can reproduce the results later. This should not merely be a transcript of what you typed: it should be more like a true lab notebook, in which you briefly note down what you did and what happened.
For this laboratory, you will find out some information about your local network. If you have trouble doing these exercises on your lab machines, document those problems and use SEASnet instead.
Use the command netstat to determine your local routing information.
Use ping and traceroute to deduce the latency and number of hops taken from your machine to www.engineer.ucla.edu, www.ucla.edu, www.caltech.edu, www.stanford.edu, www.u-tokyo.ac.jp, www.ox.ac.uk, www.cia.gov, and one off-campus web site of your own choice. Also, do the same thing for the primary name servers for ucla.edu, cs.ucla.edu, and seas.ucla.edu.
What can you deduce about the nature of your network connections to the outside world from the above data?
Use the above-mentioned tools, along with nslookup, host and/or dig, to investigate the quality of the DNS provisioning for the hosts www.isc.org and www.ucla.edu. How many DNS servers would have to go down or be inaccessible before DNS service would be lost? How quickly does each server respond to a simple query?
Assist your investigation by writing simple scripts that compute the average time to live (TTL) or hop limit value in ping responses, and the average number of hosts that respond to pings during a traceroute. Show the output of these scripts on your data.
Submit the following files.
All files should be ASCII text files, with no carriage returns, and with no more than 200 columns per line. The shell command:
expand lab8.txt hw8.txt | awk '/\r/ || 200 < length'
should output nothing.