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28 .\" From: @(#)ifconfig.8 8.3 (Berkeley) 1/5/94
29 .\" $FreeBSD: src/sbin/ifconfig/ifconfig.8,v 1.85 2004/07/27 09:51:49 yar Exp $
30 .\" $DragonFly: src/sbin/ifconfig/ifconfig.8,v 1.9 2006/02/17 19:33:32 swildner Exp $
37 .Nd configure network interface parameters
74 utility is used to assign an address
75 to a network interface and/or configure
76 network interface parameters.
79 utility must be used at boot time to define the network address
80 of each interface present on a machine; it may also be used at
81 a later time to redefine an interface's address
82 or other operating parameters.
84 The following options are available:
85 .Bl -tag -width indent
88 .Tn DARPA Ns -Internet
90 the address is either a host name present in the host name data
95 Internet address expressed in the Internet standard
98 It is also possible to use the CIDR notation (also known as the
99 slash notation) to include the netmask.
100 That is, one can specify an address like
105 family, it is also possible to specify the prefix length using the slash
110 parameter below for more information.
111 .\" For the Xerox Network Systems(tm) family,
113 .\" .Ar net:a.b.c.d.e.f ,
116 .\" is the assigned network number (in decimal),
117 .\" and each of the six bytes of the host number,
121 .\" are specified in hexadecimal.
122 .\" The host number may be omitted on IEEE 802 protocol
123 .\" (Ethernet, FDDI, and Token Ring) interfaces,
124 .\" which use the hardware physical address,
125 .\" and on interfaces other than the first.
128 .\" family, addresses are specified as a long hexadecimal string,
129 .\" as in the Xerox family.
130 .\" However, two consecutive dots imply a zero
131 .\" byte, and the dots are optional, if the user wishes to (carefully)
132 .\" count out long strings of digits in network byte order.
137 is specified as a series of colon-separated hex digits.
139 e.g.\& set a new MAC address on an ethernet interface, though the
140 mechanism used is not ethernet-specific.
141 If the interface is already
142 up when this option is used, it will be briefly brought down and
143 then brought back up again in order to ensure that the receive
144 filter in the underlying ethernet hardware is properly reprogrammed.
145 .It Ar address_family
148 which affects interpretation of the remaining parameters.
149 Since an interface can receive transmissions in differing protocols
150 with different naming schemes, specifying the address family is recommended.
151 The address or protocol families currently
170 Specify the address of the correspondent on the other end
171 of a point to point link.
174 parameter is a string of the form
180 The following parameters may be set with
182 .Bl -tag -width indent
187 Introduced for compatibility
191 Establish an additional network address for this interface.
192 This is sometimes useful when changing network numbers, and
193 one wishes to accept packets addressed to the old interface.
194 If the address is on the same subnet as the first network address
195 for this interface, a non-conflicting netmask must be given.
200 Remove the network address specified.
201 This would be used if you incorrectly specified an alias, or it
202 was no longer needed.
203 If you have incorrectly set an NS address having the side effect
204 of specifying the host portion, removing all NS addresses will
205 allow you to respecify the host portion.
208 Specify that the address configured is an anycast address.
209 Based on the current specification,
210 only routers may configure anycast addresses.
211 Anycast address will not be used as source address of any of outgoing
214 Enable the use of the Address Resolution Protocol
217 between network level addresses and link level addresses (default).
218 This is currently implemented for mapping between
223 802 48-bit MAC addresses (Ethernet, FDDI, and Token Ring addresses).
225 Disable the use of the Address Resolution Protocol
229 Specify the address to use to represent broadcasts to the
231 The default broadcast address is the address with a host part of all 1's.
233 Enable driver dependent debugging code; usually, this turns on
234 extra console error logging.
236 Disable driver dependent debugging code.
246 Put interface into permanently promiscuous mode.
248 Disable permanently promiscuous mode.
256 When an interface is marked
258 the system will not attempt to
259 transmit messages through that interface.
260 If possible, the interface will be reset to disable reception as well.
261 This action does not automatically disable routes using the interface.
265 (lowermost 64bit of an IPv6 address)
268 .\" This is used to specify an Internet host who is willing to receive
269 .\" ip packets encapsulating NS packets bound for a remote network.
270 .\" An apparent point to point link is constructed, and
271 .\" the address specified will be taken as the NS address and network
272 .\" of the destination.
273 .\" IP encapsulation of
275 .\" packets is done differently.
277 If the driver supports the media selection system, set the media type
280 Some interfaces support the mutually exclusive use of one of several
281 different physical media connectors.
282 For example, a 10Mb/s Ethernet
283 interface might support the use of either
285 or twisted pair connectors.
286 Setting the media type to
288 would change the currently active connector to the AUI port.
291 would activate twisted pair.
292 Refer to the interfaces' driver
293 specific documentation or man page for a complete list of the
295 .It Cm mediaopt Ar opts
296 If the driver supports the media selection system, set the specified
297 media options on the interface.
301 is a comma delimited list of options to apply to the interface.
302 Refer to the interfaces' driver specific man page for a complete
303 list of available options.
304 .It Fl mediaopt Ar opts
305 If the driver supports the media selection system, disable the
306 specified media options on the interface.
308 If the driver supports the media selection system, set the specified
309 operating mode on the interface to
311 For IEEE 802.11 wireless interfaces that support multiple operating modes
312 this directive is used to select between 802.11a
320 Set the interface name to
322 .It Cm rxcsum , txcsum
323 If the driver supports user-configurable checksum offloading,
324 enable receive (or transmit) checksum offloading on the interface.
325 Some drivers may not be able to enable these flags independently
326 of each other, so setting one may also set the other.
327 The driver will offload as much checksum work as it can reliably
328 support, the exact level of offloading varies between drivers.
329 .\".It Fl rxcsum , Fl txcsum
330 .\"If the driver supports user-configurable checksum offloading,
331 .\"disable receive (or transmit) checksum offloading on the interface.
332 .\"These settings may not always be independent of each other.
334 .\"If the driver has user-configurable
336 .\"support, select the polling mode on the interface.
338 .\"If the driver has user-configurable
340 .\"support, select the interrupt mode on the interface.
341 .It Cm tunnel Ar src_addr dest_addr
342 (IP tunnel devices only.)
343 Configure the physical source and destination address for IP tunnel
350 are interpreted as the outer source/destination for the encapsulating
353 Unconfigure the physical source and destination address for IP tunnel
354 interfaces previously configured with
357 Create the specified network pseudo-device.
358 If the interface is given without a unit number, try to create a new
359 device with an arbitrary unit number.
360 If creation of an arbitrary device is successful, the new device name is
361 printed to standard output.
363 Destroy the specified network pseudo-device.
378 .It Cm vlan Ar vlan_tag
379 If the interface is a
381 pseudo interface, set the VLAN tag value
384 This value is a 16-bit number which is used to create an 802.1Q
385 VLAN header for packets sent from the
392 must both be set at the same time.
393 .It Cm vlandev Ar iface
394 If the interface is a
396 pseudo device, associate physical interface
399 Packets transmitted through the
402 diverted to the specified physical interface
404 with 802.1Q VLAN encapsulation.
405 Packets with 802.1Q encapsulation received
406 by the parent interface with the correct VLAN tag will be diverted to
412 interface is assigned a
413 copy of the parent interface's flags and the parent's ethernet address.
418 must both be set at the same time.
421 interface already has
422 a physical interface associated with it, this command will fail.
424 change the association to another physical interface, the existing
425 association must be cleared first.
427 Note: if the hardware tagging capability
428 is set on the parent interface, the
431 interface's behavior changes:
434 interface recognizes that the
435 parent interface supports insertion and extraction of VLAN tags on its
436 own (usually in firmware) and that it should pass packets to and from
437 the parent unaltered.
438 .It Fl vlandev Ar iface
441 pseudo device, disassociate the physical interface
444 This breaks the link between the
446 interface and its parent,
447 clears its VLAN tag, flags and its link address and shuts the interface down.
448 .It Cm vlanmtu , vlanhwtag
449 If the driver offers user-configurable VLAN support, enable
450 reception of extended frames or tag processing in hardware,
452 Note that this must be issued on a physical interface associated with
457 .It Fl vlanmtu , Fl vlanhwtag
458 If the driver offers user-configurable VLAN support, disable
459 reception of extended frames or tag processing in hardware,
462 Set the routing metric of the interface to
465 The routing metric is used by the routing protocol
467 Higher metrics have the effect of making a route
468 less favorable; metrics are counted as addition hops
469 to the destination network or host.
471 Set the maximum transmission unit of the interface to
473 default is interface specific.
474 The MTU is used to limit the size of packets that are transmitted on an
476 Not all interfaces support setting the MTU, and some interfaces have
478 .It Cm netmask Ar mask
481 Specify how much of the address to reserve for subdividing
482 networks into sub-networks.
483 The mask includes the network part of the local address
484 and the subnet part, which is taken from the host field of the address.
485 The mask can be specified as a single hexadecimal number
488 with a dot-notation Internet address,
489 or with a pseudo-network name listed in the network table
491 The mask contains 1's for the bit positions in the 32-bit address
492 which are to be used for the network and subnet parts,
493 and 0's for the host part.
494 The mask should contain at least the standard network portion,
495 and the subnet field should be contiguous with the network
498 The netmask can also be specified in CIDR notation after the address.
501 option above for more information.
502 .It Cm prefixlen Ar len
506 bits are reserved for subdividing networks into sub-networks.
509 must be integer, and for syntactical reason it must be between 0 to 128.
510 It is almost always 64 under the current IPv6 assignment rule.
511 If the parameter is omitted, 64 is used.
513 The prefix can also be specified using the slash notation after the address.
516 option above for more information.
519 .\" .It Cm nsellength Ar n
522 .\" This specifies a trailing number of bytes for a received
524 .\" used for local identification, the remaining leading part of which is
527 .\" (Network Entity Title).
528 .\" The default value is 1, which is conformant to US
530 .\" When an ISO address is set in an ifconfig command,
533 .\" which is being specified.
536 .\" 20 hex digits should be
539 .\" to be assigned to the interface.
540 .\" There is some evidence that a number different from 1 may be useful
543 .\" 37 type addresses.
544 .It Cm range Ar netrange
545 Under appletalk, set the interface to respond to a
548 .Ar startnet Ns - Ns Ar endnet .
549 Appletalk uses this scheme instead of
552 implements it internally as a set of netmasks.
557 Introduced for compatibility
561 The argument following this specifies the version (phase) of the
562 Appletalk network attached to the interface.
563 Values of 1 or 2 are permitted.
565 .It Cm link Op Cm 0 No - Cm 2
567 Enable special processing of the link level of the interface.
568 These three options are interface specific in actual effect, however,
569 they are in general used to select special modes of operation.
571 of this is to enable SLIP compression, or to select the connector type
572 for some Ethernet cards.
573 Refer to the man page for the specific driver
574 for more information.
576 .It Fl link Op Cm 0 No - Cm 2
578 Disable special processing at the link level with the specified interface.
580 .\"Put the interface in monitor mode.
581 .\"No packets are transmitted, and received packets are discarded after
585 .\"Take the interface out of monitor mode.
589 This may be used to enable an interface after an
591 It happens automatically when setting the first address on an interface.
592 If the interface was reset when previously marked down,
593 the hardware will be re-initialized.
595 For IEEE 802.11 wireless interfaces, set the desired Service Set
596 Identifier (aka network name).
597 The SSID is a string up to 32 characters
598 in length and may be specified as either a normal string or in
599 hexadecimal when proceeded by
601 Additionally, the SSID may be cleared by setting it to
610 .It Cm stationname Ar name
611 For IEEE 802.11 wireless interfaces, set the name of this station.
612 It appears that the station name is not really part of the IEEE 802.11
613 protocol though all interfaces seem to support it.
615 seems to be meaningful to identical or virtually identical equipment.
616 Setting the station name is identical in syntax to setting the SSID.
617 .It Cm station Ar name
624 .It Cm channel Ar number
625 For IEEE 802.11 wireless interfaces, set the desired channel.
626 Channels range from 1 to 14, but the exact selection available
627 depends on the region your adaptor was manufactured for.
629 the channel to 0 will give you the default for your adaptor.
631 adaptors ignore this setting unless you are in ad-hoc mode.
632 .It Cm authmode Ar mode
633 For IEEE 802.11 wireless interfaces, set the desired authentication mode
634 in infrastructure mode.
635 Not all adaptors support all modes.
642 Modes are case insensitive.
644 For IEEE 802.11 wireless interfaces, enable powersave mode.
646 For IEEE 802.11 wireless interfaces, disable powersave mode.
647 .It Cm powersavesleep Ar sleep
648 For IEEE 802.11 wireless interfaces, set the desired max powersave sleep
649 time in milliseconds.
650 .It Cm protmode Ar technique
651 For IEEE 802.11 wireless interfaces operating in 11g, use the specified
653 for protecting OFDM frames in a mixed 11b/11g network.
654 The set of valid techniques is
661 Technique names are case insensitive.
662 .It Cm rtsthreshold Ar length
663 For IEEE 802.11 wireless interfaces, set the threshold for which
664 transmitted frames are preceded by transmission of an
670 is the frame size in bytes and must be in the range 1 to 2312.
671 Not all adaptors support setting the RTS threshold.
672 .It Cm txpower Ar power
673 For IEEE 802.11 wireless interfaces, set the power used to transmit frames.
677 is a unitless value in the range 0 to 100 that is interpreted
678 by drivers to derive a device-specific value.
679 Out of range values are truncated.
680 Typically only a few discreet power settings are available and
681 the driver will use the setting closest to the specified value.
682 Not all adaptors support changing the transmit power.
683 .It Cm wepmode Ar mode
684 For IEEE 802.11 wireless interfaces, set the desired WEP mode.
685 Not all adaptors support all modes.
686 The set of valid modes is
693 mode explicitly tells the adaptor to allow association with access
694 points which allow both encrypted and unencrypted traffic.
697 means that the access point must only allow encrypted connections.
700 is generally another name for
702 Modes are case insensitive.
703 .It Cm weptxkey Ar index
704 For IEEE 802.11 wireless interfaces, set the WEP key to be used for
706 .It Cm wepkey Ar key Ns | Ns Ar index : Ns Ar key
707 For IEEE 802.11 wireless interfaces, set the selected WEP key.
710 is not given, key 1 is set.
711 A WEP key will be either 5 or 13
712 characters (40 or 104 bits) depending of the local network and the
713 capabilities of the adaptor.
714 It may be specified either as a plain
715 string or as a string of hexadecimal digits proceeded by
717 For maximum portability, hex keys are recommended;
718 the mapping of text keys to WEP encryption is usually driver-specific.
721 drivers do this mapping differently to
723 A key may be cleared by setting it to
725 If WEP is supported then there are at least four keys.
726 Some adaptors support more than four keys.
727 If that is the case, then the first four keys
728 (1-4) will be the standard temporary keys and any others will be adaptor
729 specific keys such as permanent keys stored in NVRAM.
731 Another way of saying
737 Another way of saying
743 Another way of saying:
745 .Dq Li "wepmode on weptxkey 1 wepkey 1:key wepkey 2:- wepkey 3:- wepkey 4:-" .
752 .Ar n : k1 , k2 , k3 , k4
755 Another way of saying
757 .Dq Li "wepmode on weptxkey n wepkey 1:k1 wepkey 2:k2 wepkey 3:k3 wepkey 4:k4" .
763 Another way of saying
773 utility displays the current configuration for a network interface
774 when no optional parameters are supplied.
775 If a protocol family is specified,
777 will report only the details specific to that protocol family.
779 If the driver does supports the media selection system, the supported
780 media list will be included in the output.
784 flag is passed before an interface name,
786 will display the capability list and all
787 of the supported media for the specified interface.
790 flag is supplied, address lifetime is displayed for IPv6 addresses,
791 as time offset string.
795 flag may be used instead of an interface name.
798 to display information about all interfaces in the system.
801 flag limits this to interfaces that are down, and
803 limits this to interfaces that are up.
804 When no arguments are given,
810 flag may be used to list all available interfaces on the system, with
811 no other additional information.
812 Use of this flag is mutually exclusive
813 with all other flags and commands, except for
815 (only list interfaces that are down)
818 (only list interfaces that are up).
822 flag may be used to list all of the interface cloners available on
823 the system, with no additional information.
824 Use of this flag is mutually exclusive with all other flags and commands.
826 Only the super-user may modify the configuration of a network interface.
828 The media selection system is relatively new and only some drivers support
829 it (or have need for it).
831 Messages indicating the specified interface does not exist, the
832 requested address is unknown, or the user is not privileged and
833 tried to alter an interface's configuration.
848 Basic IPv6 node operation requires a link-local address on each
849 interface configured for IPv6.
850 Normally, such an address is automatically configured by the
851 kernel on each interface added to the system; this behaviour may
852 be disabled by setting the sysctl MIB variable
853 .Va net.inet6.ip6.auto_linklocal
856 If you delete such an address using
858 the kernel may act very oddly.
859 Do this at your own risk.