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.
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.
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.