ping 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
pingfor 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.
traceroutecommand 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.
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 -r. Can you make sense of the display, and the various options?
 It usually lives in either the
/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:
could also alter your shell startup file to add the appropriate directory to
your default path.