How to Display Network Interface Status

The i option of netstat shows the state of the network interfaces that are configured with the machine where you ran the command.

On the command line, type the following command:

% netstat -i

netstat -i produced the following sample display:

 
Name Mtu  Net/Dest     Address   Ipkts    Ierrs Opkts    Oerrs  Collis  Queue
le0  1500 b5-spd-2f-cm tatra     14093893 8492  10174659 1119   2314178   0
lo0  8232 loopback     localhost 92997622 5442  12451748 0      775125    0

Using this display, you can determine the number of packets a machine transmits and receives on each network. For example, the input packet count (Ipkts) that are displayed for a server can increase each time a client tries to boot, while the output packet count (Opkts) remains steady. This outcome suggests that the server is seeing the boot request packets from the client, but does not realize that the server is supposed to respond to them. This confusion might be caused by an incorrect address in the hosts, ipnodes, or ethers database.

However, if the input packet count is steady over time, then the machine does not see the packets at all. This outcome suggests a different type of failure, possibly a hardware problem.