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IFCONFIG(8)		FreeBSD	System Manager's Manual		   IFCONFIG(8)

NAME
     ifconfig -- configure network interface parameters

SYNOPSIS
     ifconfig [-L] [-m]	interface [create] [address_family] [address
	      [dest_address]] [parameters]
     ifconfig interface	destroy
     ifconfig -a [-L] [-d] [-m]	[-u] [address_family]
     ifconfig -l [-d] [-u] [address_family]
     ifconfig [-L] [-d]	[-m] [-u] [-C]

DESCRIPTION
     Ifconfig is used to assign	an address to a	network	interface and/or con-
     figure network interface parameters.  Ifconfig must be used at boot time
     to	define the network address of each interface present on	a machine; it
     may also be used at a later time to redefine an interface's address or
     other operating parameters.

     The following options are available:

     address
	     For the DARPA-Internet family, the	address	is either a host name
	     present in	the host name data base, hosts(5), or a	DARPA Internet
	     address expressed in the Internet standard	``dot notation''.

	     It	is also	possible to use	the CIDR notation (also	known as the
	     slash notation) to	include	the netmask.  That is, one can specify
	     an	address	like 192.168.0.1/16.

	     For ``inet6'' family, it is also possible to specify the prefix
	     length using the slash notation, like ::1/128.  See the prefixlen
	     parameter below for more information.

     address_family
	     Specify the address family	which affects interpretation of	the
	     remaining parameters.  Since an interface can receive transmis-
	     sions in differing	protocols with different naming	schemes, spec-
	     ifying the	address	family is recommended.	The address or proto-
	     col families currently supported are ``inet'', ``inet6'',
	     ``atalk'',	``ether'', and ``ipx''.

     dest_address
	     Specify the address of the	correspondent on the other end of a
	     point to point link.

     interface
	     This parameter is a string	of the form ``name unit'', for exam-
	     ple, ``ed0''.

     The following parameters may be set with ifconfig:

     add     Another name for the alias	parameter.  Introduced for compatibil-
	     ity with BSD/OS.

     alias   Establish an additional network address for this interface.  This
	     is	sometimes useful when changing network numbers,	and one	wishes
	     to	accept packets addressed to the	old interface.	If the address
	     is	on the same subnet as the first	network	address	for this
	     interface,	a netmask of 0xffffffff	has to be specified.

     -alias  Remove the	network	address	specified.  This would be used if you
	     incorrectly specified an alias, or	it was no longer needed.  If
	     you have incorrectly set an NS address having the side effect of
	     specifying	the host portion, removing all NS addresses will allow
	     you to respecify the host portion.

     anycast
	     (Inet6 only.)  Specify that the address configured	is an anycast
	     address.  Based on	the current specification, only	routers	may
	     configure anycast addresses.  Anycast address will	not be used as
	     source address of any of outgoing IPv6 packets.

     arp     Enable the	use of the Address Resolution Protocol (arp(4))	in
	     mapping between network level addresses and link level addresses
	     (default).	 This is currently implemented for mapping between
	     DARPA Internet addresses and IEEE 802 48-bit MAC addresses	(Eth-
	     ernet, FDDI, and Token Ring addresses).

     -arp    Disable the use of	the Address Resolution Protocol	(arp(4)).

     broadcast
	     (Inet only.)  Specify the address to use to represent broadcasts
	     to	the network.  The default broadcast address is the address
	     with a host part of all 1's.

     debug   Enable driver dependent debugging code; usually, this turns on
	     extra console error logging.

     -debug  Disable driver dependent debugging	code.

     delete  Another name for the -alias parameter.

     down    Mark an interface ``down''.  When an interface is marked
	     ``down'', the system will not attempt to transmit messages
	     through that interface.  If possible, the interface will be reset
	     to	disable	reception as well.  This action	does not automatically
	     disable routes using the interface.

     ether   Another name for the lladdr parameter.

     lladdr addr
	     Set the link-level	address	on an interface.  This can be used to
	     e.g. set a	new MAC	address	on an ethernet interface, though the
	     mechanism used is not ethernet-specific.  The address addr	is
	     specified as a series of colon-separated hex digits.  If the
	     interface is already up when this option is used, it will be
	     briefly brought down and then brought back	up again in order to
	     ensure that the receive filter in the underlying ethernet hard-
	     ware is properly reprogrammed.

     media type
	     If	the driver supports the	media selection	system,	set the	media
	     type of the interface to type.  Some interfaces support the mutu-
	     ally exclusive use	of one of several different physical media
	     connectors.  For example, a 10Mb/s	Ethernet interface might sup-
	     port the use of either AUI	or twisted pair	connectors.  Setting
	     the media type to ``10base5/AUI'' would change the	currently
	     active connector to the AUI port.	Setting	it to ``10baseT/UTP''
	     would activate twisted pair.  Refer to the	interfaces' driver
	     specific documentation or man page	for a complete list of the
	     available types.

     mediaopt opts
	     If	the driver supports the	media selection	system,	set the	speci-
	     fied media	options	on the interface.  The opts argument is	a
	     comma delimited list of options to	apply to the interface.	 Refer
	     to	the interfaces'	driver specific	man page for a complete	list
	     of	available options.

     -mediaopt opts
	     If	the driver supports the	media selection	system,	disable	the
	     specified media options on	the interface.

     tunnel src_addr dest_addr
	     (IP tunnel	devices	only.)	Configure the physical source and des-
	     tination address for IP tunnel interfaces (gif(4)).  The argu-
	     ments src_addr and	dest_addr are interpreted as the outer
	     source/destination	for the	encapsulating IPv4/IPv6	header.

     deletetunnel
	     Unconfigure the physical source and destination address for IP
	     tunnel interfaces previously configured with tunnel.

     create  Create the	specified network pseudo-device.  If the interface is
	     given without a unit number, try to create	a new device with an
	     arbitrary unit number.  If	creation of an arbitrary device	is
	     successful, the new device	name is	printed	to standard output.

     destroy
	     Destroy the specified network pseudo-device.

     plumb   Another name for the create parameter.  Included for Solaris com-
	     patibility.

     unplumb
	     Another name for the destroy parameter.  Included for Solaris
	     compatibility.

     vlan vlan_tag
	     If	the interface is a vlan	pseudo interface, set the vlan tag
	     value to vlan_tag.	 This value is a 16-bit	number which is	used
	     to	create an 802.1Q vlan header for packets sent from the vlan
	     interface.	 Note that vlan	and vlandev must both be set at	the
	     same time.

     vlandev iface
	     If	the interface is a vlan	pseudo device, associate physical
	     interface iface with it.  Packets transmitted through the vlan
	     interface will be diverted	to the specified physical interface
	     iface with	802.1Q vlan encapsulation.  Packets with 802.1Q	encap-
	     sulation received by the parent interface with the	correct	vlan
	     tag will be diverted to the associated vlan pseudo-interface.
	     The vlan interface	is assigned a copy of the parent interface's
	     flags and the parent's ethernet address.  The vlandev and vlan
	     must both be set at the same time.	 If the	vlan interface already
	     has a physical interface associated with it, this command will
	     fail.  To change the association to another physical interface,
	     the existing association must be cleared first.

	     Note: if the link0	flag is	set on the vlan	interface, the vlan
	     pseudo interface's	behavior changes: the link0 tells the vlan
	     interface that the	parent interface supports insertion and
	     extraction	of vlan	tags on	its own	(usually in firmware) and that
	     it	should pass packets to and from	the parent unaltered.

     -vlandev iface
	     If	the driver is a	vlan pseudo device, disassociate the physical
	     interface iface from it.  This breaks the link between the	vlan
	     interface and its parent, clears its vlan tag, flags and its link
	     address and shuts the interface down.

     metric n
	     Set the routing metric of the interface to	n, default 0.  The
	     routing metric is used by the routing protocol (routed(8)).
	     Higher metrics have the effect of making a	route less favorable;
	     metrics are counted as addition hops to the destination network
	     or	host.

     mtu n   Set the maximum transmission unit of the interface	to n, default
	     is	interface specific.  The MTU is	used to	limit the size of
	     packets that are transmitted on an	interface.  Not	all interfaces
	     support setting the MTU, and some interfaces have range restric-
	     tions.

     netmask mask
	     (Inet only.)  Specify how much of the address to reserve for sub-
	     dividing networks into sub-networks.  The mask includes the net-
	     work part of the local address and	the subnet part, which is
	     taken from	the host field of the address.	The mask can be	speci-
	     fied as a single hexadecimal number with a	leading	`0x', with a
	     dot-notation Internet address, or with a pseudo-network name
	     listed in the network table networks(5).  The mask	contains 1's
	     for the bit positions in the 32-bit address which are to be used
	     for the network and subnet	parts, and 0's for the host part.  The
	     mask should contain at least the standard network portion,	and
	     the subnet	field should be	contiguous with	the network portion.

	     The netmask can also be specified in CIDR notation	after the
	     address.  See the address option above for	more information.

     prefixlen len
	     (Inet6 only.)  Specify that len bits are reserved for subdividing
	     networks into sub-networks.  The len must be integer, and for
	     syntactical reason	it must	be between 0 to	128.  It is almost
	     always 64 under the current IPv6 assignment rule.	If the parame-
	     ter is omitted, 64	is used.

	     The prefix	can also be specified using the	slash notation after
	     the address.  See the address option above	for more information.

     range netrange
	     Under appletalk, set the interface	to respond to a	netrange of
	     the form startnet-endnet.	Appletalk uses this scheme instead of
	     netmasks though FreeBSD implements	it internally as a set of net-
	     masks.

     remove  Another name for the -alias parameter.  Introduced	for compati-
	     bility with BSD/OS.

     phase   The argument following this specifies the version (phase) of the
	     Appletalk network attached	to the interface.  Values of 1 or 2
	     are permitted.

     link[0-2]
	     Enable special processing of the link level of the	interface.
	     These three options are interface specific	in actual effect, how-
	     ever, they	are in general used to select special modes of opera-
	     tion.  An example of this is to enable SLIP compression, or to
	     select the	connector type for some	Ethernet cards.	 Refer to the
	     man page for the specific driver for more information.

     -link[0-2]
	     Disable special processing	at the link level with the specified
	     interface.

     up	     Mark an interface ``up''.	This may be used to enable an inter-
	     face after	an ``ifconfig down''.  It happens automatically	when
	     setting the first address on an interface.	 If the	interface was
	     reset when	previously marked down,	the hardware will be re-ini-
	     tialized.

     ssid ssid
	     For IEEE 802.11 wireless interfaces, set the desired Service Set
	     Identifier	(aka network name).  The SSID is a string up to	32
	     characters	in length and may be specified as either a normal
	     string or in hexadecimal when proceeded by	`0x'.  Additionally,
	     the SSID may be cleared by	setting	it to `-'.

     nwid ssid
	     Another name for the ssid parameter.  Included for	NetBSD compat-
	     ibility.

     stationname name
	     For IEEE 802.11 wireless interfaces, set the name of this sta-
	     tion.  It appears that the	station	name is	not really part	of the
	     IEEE 802.11 protocol though all interfaces	seem to	support	it.
	     As	such it	only seems to be meaningful to identical or virtually
	     identical equipment.  Setting the station name is identical in
	     syntax to setting the SSID.

     station name
	     Another name for the stationname parameter.  Included for BSD/OS
	     compatibility.

     channel number
	     For IEEE 802.11 wireless interfaces, set the desired channel.
	     Channels range from 1 to 14, but the exact	selection available
	     depends on	the region your	adaptor	was manufactured for.  Setting
	     the channel to 0 will give	you the	default	for your adaptor.
	     Many adaptors ignore this setting unless you are in ad-hoc	mode.

     authmode mode
	     For IEEE 802.11 wireless interfaces, set the desired authentica-
	     tion mode in infrastructure mode.	Not all	adaptors support all
	     modes.  The set of	valid modes is ``none'', ``open'', and
	     ``shared''.  Modes	are case insensitive.

     powersave
	     For IEEE 802.11 wireless interfaces, enable powersave mode.

     -powersave
	     For IEEE 802.11 wireless interfaces, disable powersave mode.

     powersavesleep sleep
	     For IEEE 802.11 wireless interfaces, set the desired max power-
	     save sleep	time in	milliseconds.

     wepmode mode
	     For IEEE 802.11 wireless interfaces, set the desired WEP mode.
	     Not all adaptors support all modes.  The set of valid modes is
	     ``off'', ``on'', and ``mixed''.  ``Mixed''	mode explicitly	tells
	     the adaptor to allow association with access points which allow
	     both encrypted and	unencrypted traffic.  On these adaptors,
	     ``on'' means that the access point	must only allow	encrypted con-
	     nections.	On other adaptors, ``on'' is generally another name
	     for ``mixed''.  Modes are case insensitive.

     weptxkey index
	     For IEEE 802.11 wireless interfaces, set the WEP key to be	used
	     for transmission.

     wepkey key|index:key
	     For IEEE 802.11 wireless interfaces, set the selected WEP key.
	     If	an index is not	given, key 1 is	set.  A	WEP key	will be	either
	     5 or 13 characters	(40 or 104 bits) depending of the local	net-
	     work and the capabilities of the adaptor.	It may be specified
	     either as a plain string or as a string of	hexadecimal digits
	     proceeded by `0x'.	 A key may be cleared by setting it to `-'.
	     If	WEP is supported then there are	at least four keys.  Some
	     adaptors support more than	four keys.  If that is the case, then
	     the first four keys (1-4) will be the standard temporary keys and
	     any others	will be	adaptor	specific keys such as permanent	keys
	     stored in NVRAM.

     wep     Another way of saying wepmode on.	Included for BSD/OS compati-
	     bility.

     -wep    Another way of saying wepmode off.	 Included for BSD/OS compati-
	     bility.

     nwkey key
	     Another way of saying:

	     ``wepmode on weptxkey 1 wepkey 1:key wepkey 2:- wepkey 3:-	wepkey
	     4:-''.

	     Included for NetBSD compatibility.

     nwkey n:k1,k2,k3,k4
	     Another way of saying

	     ``wepmode on weptxkey n wepkey 1:k1 wepkey	2:k2 wepkey 3:k3
	     wepkey 4:k4''.

	     Included for NetBSD compatibility.

     -nwkey  Another way of saying wepmode off.

	     Included for NetBSD compatibility.

     Ifconfig displays the current configuration for a network interface when
     no	optional parameters are	supplied.  If a	protocol family	is specified,
     ifconfig will report only the details specific to that protocol family.

     If	the driver does	supports the media selection system, the supported
     media list	will be	included in the	output.

     If	the -m flag is passed before an	interface name,	ifconfig will display
     all of the	supported media	for the	specified interface.  If -L flag is
     supplied, address lifetime	is displayed for IPv6 addresses, as time off-
     set string.

     Optionally, the -a	flag may be used instead of an interface name.	This
     flag instructs ifconfig to	display	information about all interfaces in
     the system.  The -d flag limits this to interfaces	that are down, and -u
     limits this to interfaces that are	up.  When no arguments are given, -a
     is	implied.

     The -l flag may be	used to	list all available interfaces on the system,
     with no other additional information.  Use	of this	flag is	mutually
     exclusive with all	other flags and	commands, except for -d	(only list
     interfaces	that are down) and -u (only list interfaces that are up).

     The -C flag may be	used to	list all of the	interface cloners available on
     the system, with no additional information.  Use of this flag is mutually
     exclusive with all	other flags and	commands.

     Only the super-user may modify the	configuration of a network interface.

NOTES
     The media selection system	is relatively new and only some	drivers	sup-
     port it (or have need for it).

DIAGNOSTICS
     Messages indicating the specified interface does not exist, the requested
     address is	unknown, or the	user is	not privileged and tried to alter an
     interface's configuration.

BUGS
     IPv6 link-local addresses are required for	several	basic communication
     between IPv6 node.	 If they are deleted by	ifconfig manually, the kernel
     might show	very strange behavior.	So, such manual	deletions are strongly
     discouraged.

SEE ALSO
     netstat(1), netintro(4), rc(8), routed(8)

HISTORY
     The ifconfig command appeared in 4.2BSD.

FreeBSD	10.1			 July 2, 2001			  FreeBSD 10.1

NAME | SYNOPSIS | DESCRIPTION | NOTES | DIAGNOSTICS | BUGS | SEE ALSO | HISTORY

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