Книга: Linux Network Administrator Guide, Second Edition

Displaying Interface Statistics

Displaying Interface Statistics

When invoked with the -i flag, netstat displays statistics for the network interfaces currently configured. If the -a option is also given, it prints all interfaces present in the kernel, not only those that have been configured currently. On vstout, 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-OVR Flags
lo 0 0 3185 0 0 0 3185 0 0 0 BLRU
eth0 1500 0 972633 17 20 120 628711 217 0 0 BRU

The MTU and Met fields show the current MTU and metric values for that interface. The RX and TX columns show how many packets have been received or transmitted error-free (RX-OK / TX-OK) or 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 characters are one-character versions of the long flag names that are printed when you display the interface configuration with ifconfig:

A broadcast address has been set.

L

This interface is a loopback device.

M

All packets are received (promiscuous mode).

O

ARP is turned off for this interface.

This is a point-to-point connection.

R

Interface is running.

U

Interface is up.

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