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

NAME
     ifconfig -- configure network interface parameters

SYNOPSIS
     ifconfig [-N] interface address_family [address [dest_address]]
	      [parameters]
     ifconfig [-hLmNvz]	interface [protocol_family]
     ifconfig -a [-bdhLNmsuvz] [protocol_family]
     ifconfig -l [-bdsu]
     ifconfig -s interface
     ifconfig -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.

     Available operands	for ifconfig:

     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".	 For
	     the Xerox Network Systems(tm) family, addresses are
	     net:a.b.c.d.e.f, where net	is the assigned	network	number (in
	     decimal), and each	of the six bytes of the	host number, a through
	     f,	are specified in hexadecimal.  The host	number may be omitted
	     on	Ethernet interfaces, which use the hardware physical address,
	     and on interfaces other than the first.  For the ISO family, ad-
	     dresses are specified as a	long hexadecimal string, as in the Xe-
	     rox family.  However, two consecutive dots	imply a	zero byte, and
	     the dots are optional, if the user	wishes to (carefully) count
	     out long strings of digits	in network byte	order.

     address_family
	     Specifies 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",
	     "iso", and	"link".

     interface
	     The interface parameter is	a string of the	form "name unit", for
	     example, "en0"

     The following parameters may be set with ifconfig:

     active	     This keyword applies when ifconfig	adds or	modifies any
		     link-layer	address.  It indicates that ifconfig should
		     "activate"	the address.  Activation makes an address the
		     default source for	transmissions on the interface.	 You
		     may not delete the	active address from an interface.  You
		     must activate some	other address, first.

     advbase n	     If	the driver is a	carp(4)	pseudo-device, set the base
		     advertisement interval to n seconds.  This	ia an 8-bit
		     number; the default value is 1 second.

     advskew n	     If	the driver is a	carp(4)	pseudo-device, skew the	adver-
		     tisement interval by n.  This is an 8-bit number; the de-
		     fault value is 0.

		     Taken together the	advbase	indicate how frequently, in
		     seconds, the host will advertise the fact that it consid-
		     ers itself	the master of the virtual host.	 The formula
		     is	advbase	+ (advskew / 256).  If the master does not ad-
		     vertise within three times	this interval, this host will
		     begin advertising as master.

     alias	     Establish an additional network address for this inter-
		     face.  This is sometimes useful when changing network
		     numbers, and one wishes to	accept packets addressed to
		     the old interface.

     -alias	     Remove the	specified network address alias.

     arp	     Enable the	use of the Address Resolution Protocol in map-
		     ping between network level	addresses and link level ad-
		     dresses (default).	 This is currently implemented for
		     mapping between DARPA Internet addresses and Ethernet ad-
		     dresses.

     -arp	     Disable the use of	the Address Resolution Protocol.

     anycast	     (inet6 only) Set the IPv6 anycast address bit.

     -anycast	     (inet6 only) Clear	the IPv6 anycast address bit.

     broadcast mask  (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.

     carpdev iface   If	the driver is a	carp(4)	pseudo-device, attach it to
		     iface.  If	not specified, the kernel will attempt to se-
		     lect an interface with a subnet matching that of the carp
		     interface.

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

     -debug	     Disable driver dependent debugging	code.

     delete	     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.  delete does	not work for IPv6 addresses.
		     Use -alias	with explicit IPv6 address instead.

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

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

     ipdst	     This is used to specify an	Internet host who is willing
		     to	receive	ip packets encapsulating NS packets bound for
		     a remote network.	An apparent point to point link	is
		     constructed, and the address specified will be taken as
		     the NS address and	network	of the destination.  IP	encap-
		     sulation of CLNP packets is done differently.

     media type	     Set the media type	of the interface to type.  Some	inter-
		     faces support the mutually	exclusive use of one of	sev-
		     eral different physical media connectors.	For example, a
		     10Mb/s Ethernet interface might support the use of	either
		     AUI or twisted pair connectors.  Setting the media	type
		     to	"10base5" or "AUI" would change	the currently active
		     connector to the AUI port.	 Setting it to "10baseT" or
		     "UTP" would activate twisted pair.	 Refer to the inter-
		     faces' driver specific man	page for a complete list of
		     the available types and the ifmedia(4) manual page	for a
		     list of media types.  See the -m flag below.

     mediaopt opts   Set the specified media options on	the interface.	opts
		     is	a comma	delimited list of options to apply to the in-
		     terface.  Refer to	the interfaces'	driver specific	man
		     page for a	complete list of available options.  Also see
		     the ifmedia(4) manual page	for a list of media options.

     -mediaopt opts  Disable the specified media options on the	interface.

     mode mode	     If	the driver supports the	media selection	system,	set
		     the specified operating mode on the interface to mode.
		     For IEEE 802.11 wireless interfaces that support multiple
		     operating modes this directive is used to select between
		     802.11a ("11a"), 802.11b ("11b"), and 802.11g ("11g") op-
		     erating modes.

     instance minst  Set the media instance to minst.  This is useful for de-
		     vices which have multiple physical	layer interfaces
		     (PHYs).  Setting the instance on such devices may not be
		     strictly required by the network interface	driver as the
		     driver may	take care of this automatically; see the
		     driver's manual page for more information.

     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.
		     Most interfaces don't support this	option.

     netmask mask    (inet, inet6, and ISO) Specify how	much of	the address to
		     reserve for subdividing networks into sub-networks.  The
		     mask includes the network part of the local address and
		     the subnet	part, which is taken from the host field of
		     the address.  The mask can	be specified as	a single hexa-
		     decimal number with a leading 0x, with a dot-notation In-
		     ternet 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 contigu-
		     ous with the network portion.

		     For INET and INET6	addresses, the netmask can also	be
		     given with	slash-notation after the address (e.g
		     192.168.17.3/24).

     nsellength	n    (ISO only)	This specifies a trailing number of bytes for
		     a received	NSAP used for local identification, the	re-
		     maining leading part of which is taken to be the NET
		     (Network Entity Title).  The default value	is 1, which is
		     conformant	to US GOSIP.  When an ISO address is set in an
		     ifconfig command, it is really the	NSAP which is being
		     specified.	 For example, in US GOSIP, 20 hex digits
		     should be specified in the	ISO NSAP to be assigned	to the
		     interface.	 There is some evidence	that a number differ-
		     ent from 1	may be useful for AFI 37 type addresses.

     state state     Explicitly	force the carp(4) pseudo-device	to enter this
		     state.  Valid states are init, backup, and	master.

     frag threshold  (IEEE 802.11 devices only)	Configure the fragmentation
		     threshold for IEEE	802.11-based wireless network inter-
		     faces.

     rts threshold   (IEEE 802.11 devices only)	Configure the RTS/CTS thresh-
		     old for IEEE 802.11-based wireless	network	interfaces.
		     This controls the number of bytes used for	the RTS/CTS
		     handshake boundary.  The threshold	can be any value be-
		     tween 0 and 2347.	The default is 2347, which indicates
		     the RTS/CTS mechanism should not be used.

     ssid id	     (IEEE 802.11 devices only)	Configure the Service Set
		     Identifier	(a.k.a.	the network name) for IEEE
		     802.11-based wireless network interfaces.	The id can ei-
		     ther be any text string up	to 32 characters in length, or
		     a series of up to 64 hexadecimal digits preceded by "0x".
		     Setting id	to the empty string allows the interface to
		     connect to	any available access point.

     nwid id	     Synonym for "ssid".

     hidessid	     (IEEE 802.11 devices only)	When operating as an access
		     point, do not broadcast the SSID in beacon	frames or re-
		     spond to probe request frames unless they are directed to
		     the ap (i.e., they	include	the ap's SSID).	 By default,
		     the SSID is included in beacon frames and undirected
		     probe request frames are answered.

     -hidessid	     (IEEE 802.11 devices only)	When operating as an access
		     point, broadcast the SSID in beacon frames	and answer and
		     respond to	undirected probe request frames	(default).

     nwkey key	     (IEEE 802.11 devices only)	Enable WEP encryption for IEEE
		     802.11-based wireless network interfaces with the key.
		     The key can either	be a string, a series of hexadecimal
		     digits preceded by	"0x", or a set of keys in the form
		     n:k1,k2,k3,k4, where n specifies which of keys will be
		     used for all transmitted packets, and four	keys, k1
		     through k4, are configured	as WEP keys.  Note that	the
		     order must	be match within	same network if	multiple keys
		     are used.	For IEEE 802.11	wireless network, the length
		     of	each key is restricted to 40 bits, i.e.	5-character
		     string or 10 hexadecimal digits, while the	WaveLAN/IEEE
		     Gold cards	accept the 104 bits (13	characters) key.

     nwkey persist   (IEEE 802.11 devices only)	Enable WEP encryption for IEEE
		     802.11-based wireless network interfaces with the persis-
		     tent key written in the network card.

     nwkey persist:key
		     (IEEE 802.11 devices only)	Write the key to the persis-
		     tent memory of the	network	card, and enable WEP encryp-
		     tion for IEEE 802.11-based	wireless network interfaces
		     with the key.

     -nwkey	     (IEEE 802.11 devices only)	Disable	WEP encryption for
		     IEEE 802.11-based wireless	network	interfaces.

     apbridge	     (IEEE 802.11 devices only)	When operating as an access
		     point, pass packets between wireless clients directly
		     (default).

     -apbridge	     (IEEE 802.11 devices only)	When operating as an access
		     point, pass packets through the system so that they can
		     be	forwared using some other mechanism.  Disabling	the
		     internal bridging is useful when traffic is to be pro-
		     cessed with packet	filtering.

     pass passphrase
		     If	the driver is a	carp(4)	pseudo-device, set the authen-
		     tication key to passphrase.  There	is no passphrase by
		     default

     powersave	     (IEEE 802.11 devices only)	Enable 802.11 power saving
		     mode.

     -powersave	     (IEEE 802.11 devices only)	Disable	802.11 power saving
		     mode.

     powersavesleep duration
		     (IEEE 802.11 devices only)	Set the	receiver sleep dura-
		     tion in milliseconds for 802.11 power saving mode.

     bssid bssid     (IEEE 802.11 devices only)	Set the	desired	BSSID for IEEE
		     802.11-based wireless network interfaces.

     -bssid	     (IEEE 802.11 devices only)	Unset the desired BSSID	for
		     IEEE 802.11-based wireless	network	interfaces.  The in-
		     terface will automatically	select a BSSID in this mode,
		     which is the default.

     chan chan	     (IEEE 802.11 devices only)	Select the channel (radio
		     frequency)	to be used for IEEE 802.11-based wireless net-
		     work interfaces.

     -chan	     (IEEE 802.11 devices only)	Unset the desired channel to
		     be	used for IEEE 802.11-based wireless network inter-
		     faces.  It	doesn't	affect the channel to be created for
		     IBSS or hostap mode.

     list scan	     (IEEE 802.11 devices only)	Display	the access points
		     and/or ad-hoc neighbors located in	the vicinity.  The -v
		     flag may be used to display long SSIDs.  -v also causes
		     received information elements to be displayed symboli-
		     cally.  Only the super-user can use this command.

     tunnel src_addr[,src_port]
		     dest_addr[,dest_port] (IP tunnel devices only) Configure
		     the physical source and destination address for IP	tunnel
		     interfaces, including gif(4).  The	arguments src_addr and
		     dest_addr are interpreted as the outer source/destination
		     for the encapsulating IPv4/IPv6 header.

		     On	a gre(4) interface in UDP mode,	the arguments src_port
		     and dest_port are interpreted as the outer	source/desti-
		     nation port for the encapsulating UDP header.

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

     create	     Create the	specified network pseudo-device.

     destroy	     Destroy the specified network pseudo-device.

     pltime n	     (inet6 only) Set preferred	lifetime for the address.

     prefixlen n     (inet and inet6 only) Effect is similar to	netmask.  but
		     you can specify by	prefix length by digits.

     deprecated	     (inet6 only) Set the IPv6 deprecated address bit.

     -deprecated     (inet6 only) Clear	the IPv6 deprecated address bit.

     tentative	     (inet6 only) Set the IPv6 tentative address bit.

     -tentative	     (inet6 only) Clear	the IPv6 tentative address bit.

     eui64	     (inet6 only) Fill interface index (lowermost 64bit	of an
		     IPv6 address) automatically.

     link[0-2]	     Enable special processing of the link level of the	inter-
		     face.  These three	options	are interface specific in ac-
		     tual effect, however, they	are in general used to select
		     special modes of operation.  An example of	this is	to en-
		     able 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.

     linkstr	     Set a link-level string parameter for the interface.
		     This functionality	varies from interface to interface.
		     Refer to the man page for the specific driver for more
		     information.

     -linkstr	     Remove an interface link-level string parameter.

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

     vhid n	     If	the driver is a	carp(4)	pseudo-device, set the virtual
		     host ID to	n.  Acceptable values are 1 to 255.

     vlan vid	     If	the interface is a vlan(4) pseudo-interface, set the
		     VLAN identifier to	vid.  These are	the first 12 bits
		     (0-4095) from a 16-bit integer used to create an 802.1Q
		     VLAN header for packets sent from the vlan(4) interface.
		     Note that vlan and	vlanif must be set at the same time.

     vlanif iface    If	the interface is a vlan(4) pseudo-interface, associate
		     the physical interface iface with it.  Packets transmit-
		     ted through the vlan(4) interface will be diverted	to the
		     specified physical	interface iface	with 802.1Q VLAN en-
		     capsulation.  Packets with	802.1Q encapsulation received
		     by	the physical interface with the	correct	VLAN tag will
		     be	diverted to the	associated vlan(4) pseudo-interface.
		     The VLAN interface	is assigned a copy of the physical in-
		     terface's flags and Ethernet address.  If the vlan(4) in-
		     terface 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 that vlanif and vlan must be set
		     at	the same time.

     agrport iface   Add iface to the agr(4) interface.

     -agrport iface  Remove iface from the agr(4) interface.

     vltime n	     (inet6 only) Set valid lifetime for the address.

     ip4csum	     Shorthand of "ip4csum-tx ip4csum-rx"

     -ip4csum	     Shorthand of "-ip4csum-tx -ip4csum-rx"

     tcp4csum	     Shorthand of "tcp4csum-tx tcp4csum-rx"

     -tcp4csum	     Shorthand of "-tcp4csum-tx	-tcp4csum-rx"

     udp4csum	     Shorthand of "udp4csum-tx udp4csum-rx"

     -udp4csum	     Shorthand of "-udp4csum-tx	-udp4csum-rx"

     tcp6csum	     Shorthand of "tcp6csum-tx tcp6csum-rx"

     -tcp6csum	     Shorthand of "-tcp6csum-tx	-tcp6csum-rx"

     udp6csum	     Shorthand of "udp6csum-tx udp6csum-rx"

     -udp6csum	     Shorthand of "-udp6csum-tx	-udp6csum-rx"

     ip4csum-tx	     Enable hardware-assisted IPv4 header checksums for	the
		     out-bound direction.

     -ip4csum-tx     Disable hardware-assisted IPv4 header checksums for the
		     out-bound direction.

     ip4csum-rx	     Enable hardware-assisted IPv4 header checksums for	the
		     in-bound direction.

     -ip4csum-rx     Disable hardware-assisted IPv4 header checksums for the
		     in-bound direction.

     tcp4csum-tx     Enable hardware-assisted TCP/IPv4 checksums for the out-
		     bound direction.

     -tcp4csum-tx    Disable hardware-assisted TCP/IPv4	checksums for the out-
		     bound direction.

     tcp4csum-rx     Enable hardware-assisted TCP/IPv4 checksums for the in-
		     bound direction.

     -tcp4csum-rx    Disable hardware-assisted TCP/IPv4	checksums for the in-
		     bound direction.

     udp4csum-tx     Enable hardware-assisted UDP/IPv4 checksums for the out-
		     bound direction.

     -udp4csum-tx    Disable hardware-assisted UDP/IPv4	checksums for the out-
		     bound direction.

     udp4csum-rx     Enable hardware-assisted UDP/IPv4 checksums for the in-
		     bound direction.

     -udp4csum-rx    Disable hardware-assisted UDP/IPv4	checksums for the in-
		     bound direction.

     tcp6csum-tx     Enable hardware-assisted TCP/IPv6 checksums for the out-
		     bound direction.

     -tcp6csum-tx    Disable hardware-assisted TCP/IPv6	checksums for the out-
		     bound direction.

     tcp6csum-rx     Enable hardware-assisted TCP/IPv6 checksums for the in-
		     bound direction.

     -tcp6csum-rx    Disable hardware-assisted TCP/IPv6	checksums for the in-
		     bound direction.

     udp6csum-tx     Enable hardware-assisted UDP/IPv6 checksums for the out-
		     bound direction.

     -udp6csum-tx    Disable hardware-assisted UDP/IPv6	checksums for the out-
		     bound direction.

     udp6csum-rx     Enable hardware-assisted UDP/IPv6 checksums for the in-
		     bound direction.

     -udp6csum-rx    Disable hardware-assisted UDP/IPv6	checksums for the in-
		     bound direction.

     tso4	     Enable hardware-assisted TCP/IPv4 segmentation on inter-
		     faces that	support	it.

     -tso4	     Disable hardware-assisted TCP/IPv4	segmentation on	inter-
		     faces that	support	it.

     tso6	     Enable hardware-assisted TCP/IPv6 segmentation on inter-
		     faces that	support	it.

     -tso6	     Disable hardware-assisted TCP/IPv6	segmentation on	inter-
		     faces that	support	it.

     maxupd n	     If	the driver is a	pfsync(4) pseudo-device, indicate the
		     maximum number of updates for a single state which	can be
		     collapsed into one.  This is an 8-bit number; the default
		     value is 128.

     syncdev iface   If	the driver is a	pfsync(4) pseudo-device, use the spec-
		     ified interface to	send and receive pfsync	state synchro-
		     nisation messages.

     -syncdev	     If	the driver is a	pfsync(4) pseudo-device, stop sending
		     pfsync state synchronisation messages over	the network.

     syncpeer peer_address
		     If	the driver is a	pfsync(4) pseudo-device, make the pf-
		     sync link point-to-point rather than using	multicast to
		     broadcast the state synchronisation messages.  The
		     peer_address is the IP address of the other host taking
		     part in the pfsync	cluster.  With this option, pfsync(4)
		     traffic can be protected using ipsec(4).

     -syncpeer	     If	the driver is a	pfsync(4) pseudo-device, broadcast the
		     packets using multicast.

     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 -s flag is passed before an	interface name,	ifconfig will attempt
     to	query the interface for	its media status.  If the interface supports
     reporting media status, and it reports that it does not appear to be con-
     nected to a network, ifconfig will	exit with status of 1 (false); other-
     wise, it will exit	with a zero (true) exit	status.	 Not all interface
     drivers support media status reporting.

     If	the -m flag is passed before an	interface name,	ifconfig will display
     all of the	supported media	for the	specified interface.  If the -L	flag
     is	supplied, address lifetime is displayed	for IPv6 addresses, as time
     offset 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.  This is also the default behaviour when no arguments are
     given to ifconfig on the command line.  When -a is	used, the output can
     be	modified by adding more	flags: -d limits this to interfaces that are
     down, -u limits this to interfaces	that are up, -b	limits this to broad-
     cast interfaces, and -s omits interfaces which appear not to be connected
     to	a network.

     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 ex-
     clusive with all other flags and commands,	except for -d (only list
     interfaces	that are down),	-u (only list interfaces that are up), -s
     (only list	interfaces that	may be connected), -b (only list broadcast
     interfaces).

     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.

     The -v flag prints	statistics on packets sent and received	on the given
     interface.	 If -h is used in conjunction with -v, the byte	statistics
     will be printed in	"human-readable" format.  The -z flag is identical to
     the -v flag except	that it	zeros the interface input and output statis-
     tics after	printing them.

     The -N flag is just the opposite of the -n	flag in	netstat(1) or in
     route(8): it tells	ifconfig to try	to resolve numbers to hostnames	or to
     service names.  The default ifconfig behavior is to print numbers instead
     of	names.

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

EXAMPLES
     Add a link-layer (MAC) address to an Ethernet:

     ifconfig sip0 link	00:11:22:33:44:55

     Add and activate a	link-layer (MAC) address:

     ifconfig sip0 link	00:11:22:33:44:55 active

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.

SEE ALSO
     netstat(1), agr(4), carp(4), ifmedia(4), netintro(4), pfsync(4), vlan(4),
     ifconfig.if(5), rc(8), routed(8)

HISTORY
     The ifconfig command appeared in 4.2BSD.

BSD			       January 28, 2012				   BSD

NAME | SYNOPSIS | DESCRIPTION | EXAMPLES | DIAGNOSTICS | SEE ALSO | HISTORY

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