Linux in a Nutshell, Fourth Edition

Name

ifconfig

Synopsis

                  ifconfig [interface]
ifconfig [interface 
                  address_family 
                  parameters 
                  addresses]

TCP/IP command. Assign an address to a network interface and/or configure network interface parameters. ifconfig is typically used at boot time to define the network address of each interface on a machine. It may be used at a later time to redefine an interface’s address or other parameters. Without arguments, ifconfig displays the current configuration for a network interface. Used with a single interface argument, ifconfig displays that particular interface’s current configuration.

Arguments

interface

String of the form name unit, for example, en0.

address_family

Since an interface may receive transmissions in differing protocols, each of which may require separate naming schemes, you can specify the address_family to change the interpretation of the remaining parameters. You may specify inet (for TCP/IP, the default), ax25 (AX.25 Packet Radio), ddp (Appletalk Phase 2), or ipx (Novell).

parameters

The following parameters may be set with ifconfig:

add address / prefixlength

Add an IPv6 address and prefix length.

allmulti/-allmulti

Enable/disable sending of incoming frames to the kernel’s network layer.

arp/-arp

Enable/disable use of the Address Resolution Protocol in mapping between network-level addresses and link-level addresses.

broadcast [address]

(inet only) Specify address to use to represent broadcasts to the network. Default is the address with a host part of all 1s (i.e., ...