INT21CN Computer Networks

Computer Networks

Practical exercises #21

  1. Use the ping[1] command to check reachability of various hosts on your nearby region of the Internet and elsewhere. If you're using Unix/Linux, investigate the many command line options which can be used to customise the operation of ping. If you're not on Unix, there are versions of ping for virtually all combinations of hardware and operating system. For example, on most MS Windows systems, a version of the ping command can be accessed through the "Run" menu.

  2. The traceroute command is available on our on-campus Unix and Linux systems, as well as for PCs and Macs. Use traceroute (judiciously -- see its documentation). NB: there are quite a few other software utilities which perform the same function as traceroute, but have a different name (eg, I know of one called "tracert" and another called "whatroute"). See what you can find on the various free software repositories.

  3. If you have access to a Unix/Linux system, give yourself a shell and try netstat. This command examines the OS kernel memory and displays the values of various Internet-related variables. Try a few of its command line options. The most interesting are probably netstat -C and netstat -r. Can you make sense of the display, and the various options?

[1] It usually lives in either the /usr/etc or /sbin directory, which may not be in your path. If you get a "Command not found" error of some kind, try typing the full pathname, for example: /usr/etc/ping. You could also alter your shell startup file to add the appropriate directory to your default path. La Trobe Uni Logo

Copyright 2003 by Philip Scott, La Trobe University.
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