The -rn option on netstat shows the default routes for your network. Routes are the paths network traffic takes
to contact a remote machine. To reach local machines on the same
network as your machine, you do not need any extra routes. To reach
the rest of the world, you need to define a default route which tells
your machine to send all traffic not belonging to your network to this
default router. You use netstat -rn to be sure you have the
default route properly defined, and then ping the default
router to be sure it is alive:
$ netstat -rn Show default routes. Routing tables Destination Gateway Flags Refs Use Interface 127.0.0.1 127.0.0.1 UH 3 0 lo0 default 127.29.13.100 UG 0 0 tok0 127.29.136 127.29.13.99 U 2 1696 tok0 $ ping 127.29.13.100 We ping the default router. PING thomas.hal.com: (127.29.13.100): 56 data bytes 64 bytes from 127.29.13.100: icmp_seq=0. time=3. ms 64 bytes from 127.29.13.100: icmp_seq=1. time=3. ms 64 bytes from 127.29.13.100: icmp_seq=2. time=4. ms [ctrl]-c User interrupts the program.