Displaying Interface Statistics

When invoked with the -i flag, netstat will display statistics for the network interfaces currently configured. If, in addition, the -a option is given, it will print all interfaces present in the kernel, not only those that have been configured currently. On vstaout, the output from netstat will look like this:

           $ netstat -i
           Kernel Interface table
           Iface   MTU Met  RX-OK RX-ERR RX-DRP RX-OVR  TX-OK TX-ERR TX-DRP TX-
           lo        0   0   3185      0      0      0   3185      0      0
           eth0   1500   0 972633     17     20    120 628711    217      0

The MTU and Met fields show the current MTU and metric value for that interface. The RX and TX columns show how many packets have been received or transmitted error free (RX-OK/TX-OK), damaged (RX-ERR/TX-ERR), how many were dropped (RX-DRP/TX-DRP), and how many were lost because of an overrun (RX-OVR/TX-OVR).

The last column shows the flags that have been set for this interface. These are one-character versions of the long flag names the are printed when you display the interface configuration with ifconfig.

B

A broadcast address has been set.

L

This interface is a loopback device

M

All packets are received (promiscuous mode).

N

Trailers are avoided.

O

ARP is turned off for this interface.

P

This is a point-to-point connection.

R Interface is running.

U Interface is up.