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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 1.7 2005/04/25 17:33:26 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.
238 Put interface into permanently promiscuous mode.
240 Disable permanently promiscuous mode.
248 When an interface is marked
250 the system will not attempt to
251 transmit messages through that interface.
252 If possible, the interface will be reset to disable reception as well.
253 This action does not automatically disable routes using the interface.
257 (lowermost 64bit of an IPv6 address)
260 .\" This is used to specify an Internet host who is willing to receive
261 .\" ip packets encapsulating NS packets bound for a remote network.
262 .\" An apparent point to point link is constructed, and
263 .\" the address specified will be taken as the NS address and network
264 .\" of the destination.
265 .\" IP encapsulation of
267 .\" packets is done differently.
269 If the driver supports the media selection system, set the media type
272 Some interfaces support the mutually exclusive use of one of several
273 different physical media connectors.
274 For example, a 10Mb/s Ethernet
275 interface might support the use of either
277 or twisted pair connectors.
278 Setting the media type to
280 would change the currently active connector to the AUI port.
283 would activate twisted pair.
284 Refer to the interfaces' driver
285 specific documentation or man page for a complete list of the
287 .It Cm mediaopt Ar opts
288 If the driver supports the media selection system, set the specified
289 media options on the interface.
293 is a comma delimited list of options to apply to the interface.
294 Refer to the interfaces' driver specific man page for a complete
295 list of available options.
296 .It Fl mediaopt Ar opts
297 If the driver supports the media selection system, disable the
298 specified media options on the interface.
300 If the driver supports the media selection system, set the specified
301 operating mode on the interface to
303 For IEEE 802.11 wireless interfaces that support multiple operating modes
304 this directive is used to select between 802.11a
312 Set the interface name to
314 .It Cm rxcsum , txcsum
315 If the driver supports user-configurable checksum offloading,
316 enable receive (or transmit) checksum offloading on the interface.
317 Some drivers may not be able to enable these flags independently
318 of each other, so setting one may also set the other.
319 The driver will offload as much checksum work as it can reliably
320 support, the exact level of offloading varies between drivers.
321 .\".It Fl rxcsum , Fl txcsum
322 .\"If the driver supports user-configurable checksum offloading,
323 .\"disable receive (or transmit) checksum offloading on the interface.
324 .\"These settings may not always be independent of each other.
326 .\"If the driver has user-configurable
328 .\"support, select the polling mode on the interface.
330 .\"If the driver has user-configurable
332 .\"support, select the interrupt mode on the interface.
333 .It Cm tunnel Ar src_addr dest_addr
334 (IP tunnel devices only.)
335 Configure the physical source and destination address for IP tunnel
342 are interpreted as the outer source/destination for the encapsulating
345 Unconfigure the physical source and destination address for IP tunnel
346 interfaces previously configured with
349 Create the specified network pseudo-device.
350 If the interface is given without a unit number, try to create a new
351 device with an arbitrary unit number.
352 If creation of an arbitrary device is successful, the new device name is
353 printed to standard output.
355 Destroy the specified network pseudo-device.
370 .It Cm vlan Ar vlan_tag
371 If the interface is a
373 pseudo interface, set the VLAN tag value
376 This value is a 16-bit number which is used to create an 802.1Q
377 VLAN header for packets sent from the
384 must both be set at the same time.
385 .It Cm vlandev Ar iface
386 If the interface is a
388 pseudo device, associate physical interface
391 Packets transmitted through the
394 diverted to the specified physical interface
396 with 802.1Q VLAN encapsulation.
397 Packets with 802.1Q encapsulation received
398 by the parent interface with the correct VLAN tag will be diverted to
404 interface is assigned a
405 copy of the parent interface's flags and the parent's ethernet address.
410 must both be set at the same time.
413 interface already has
414 a physical interface associated with it, this command will fail.
416 change the association to another physical interface, the existing
417 association must be cleared first.
419 Note: if the hardware tagging capability
420 is set on the parent interface, the
423 interface's behavior changes:
426 interface recognizes that the
427 parent interface supports insertion and extraction of VLAN tags on its
428 own (usually in firmware) and that it should pass packets to and from
429 the parent unaltered.
430 .It Fl vlandev Ar iface
433 pseudo device, disassociate the physical interface
436 This breaks the link between the
438 interface and its parent,
439 clears its VLAN tag, flags and its link address and shuts the interface down.
440 .It Cm vlanmtu , vlanhwtag
441 If the driver offers user-configurable VLAN support, enable
442 reception of extended frames or tag processing in hardware,
444 Note that this must be issued on a physical interface associated with
449 .It Fl vlanmtu , Fl vlanhwtag
450 If the driver offers user-configurable VLAN support, disable
451 reception of extended frames or tag processing in hardware,
454 Set the routing metric of the interface to
457 The routing metric is used by the routing protocol
459 Higher metrics have the effect of making a route
460 less favorable; metrics are counted as addition hops
461 to the destination network or host.
463 Set the maximum transmission unit of the interface to
465 default is interface specific.
466 The MTU is used to limit the size of packets that are transmitted on an
468 Not all interfaces support setting the MTU, and some interfaces have
470 .It Cm netmask Ar mask
473 Specify how much of the address to reserve for subdividing
474 networks into sub-networks.
475 The mask includes the network part of the local address
476 and the subnet part, which is taken from the host field of the address.
477 The mask can be specified as a single hexadecimal number
480 with a dot-notation Internet address,
481 or with a pseudo-network name listed in the network table
483 The mask contains 1's for the bit positions in the 32-bit address
484 which are to be used for the network and subnet parts,
485 and 0's for the host part.
486 The mask should contain at least the standard network portion,
487 and the subnet field should be contiguous with the network
490 The netmask can also be specified in CIDR notation after the address.
493 option above for more information.
494 .It Cm prefixlen Ar len
498 bits are reserved for subdividing networks into sub-networks.
501 must be integer, and for syntactical reason it must be between 0 to 128.
502 It is almost always 64 under the current IPv6 assignment rule.
503 If the parameter is omitted, 64 is used.
505 The prefix can also be specified using the slash notation after the address.
508 option above for more information.
511 .\" .It Cm nsellength Ar n
514 .\" This specifies a trailing number of bytes for a received
516 .\" used for local identification, the remaining leading part of which is
519 .\" (Network Entity Title).
520 .\" The default value is 1, which is conformant to US
522 .\" When an ISO address is set in an ifconfig command,
525 .\" which is being specified.
528 .\" 20 hex digits should be
531 .\" to be assigned to the interface.
532 .\" There is some evidence that a number different from 1 may be useful
535 .\" 37 type addresses.
536 .It Cm range Ar netrange
537 Under appletalk, set the interface to respond to a
540 .Ar startnet Ns - Ns Ar endnet .
541 Appletalk uses this scheme instead of
544 implements it internally as a set of netmasks.
549 Introduced for compatibility
553 The argument following this specifies the version (phase) of the
554 Appletalk network attached to the interface.
555 Values of 1 or 2 are permitted.
557 .It Cm link Op Cm 0 No - Cm 2
559 Enable special processing of the link level of the interface.
560 These three options are interface specific in actual effect, however,
561 they are in general used to select special modes of operation.
563 of this is to enable SLIP compression, or to select the connector type
564 for some Ethernet cards.
565 Refer to the man page for the specific driver
566 for more information.
568 .It Fl link Op Cm 0 No - Cm 2
570 Disable special processing at the link level with the specified interface.
572 .\"Put the interface in monitor mode.
573 .\"No packets are transmitted, and received packets are discarded after
577 .\"Take the interface out of monitor mode.
581 This may be used to enable an interface after an
583 It happens automatically when setting the first address on an interface.
584 If the interface was reset when previously marked down,
585 the hardware will be re-initialized.
587 For IEEE 802.11 wireless interfaces, set the desired Service Set
588 Identifier (aka network name).
589 The SSID is a string up to 32 characters
590 in length and may be specified as either a normal string or in
591 hexadecimal when proceeded by
593 Additionally, the SSID may be cleared by setting it to
602 .It Cm stationname Ar name
603 For IEEE 802.11 wireless interfaces, set the name of this station.
604 It appears that the station name is not really part of the IEEE 802.11
605 protocol though all interfaces seem to support it.
607 seems to be meaningful to identical or virtually identical equipment.
608 Setting the station name is identical in syntax to setting the SSID.
609 .It Cm station Ar name
616 .It Cm channel Ar number
617 For IEEE 802.11 wireless interfaces, set the desired channel.
618 Channels range from 1 to 14, but the exact selection available
619 depends on the region your adaptor was manufactured for.
621 the channel to 0 will give you the default for your adaptor.
623 adaptors ignore this setting unless you are in ad-hoc mode.
624 .It Cm authmode Ar mode
625 For IEEE 802.11 wireless interfaces, set the desired authentication mode
626 in infrastructure mode.
627 Not all adaptors support all modes.
634 Modes are case insensitive.
636 For IEEE 802.11 wireless interfaces, enable powersave mode.
638 For IEEE 802.11 wireless interfaces, disable powersave mode.
639 .It Cm powersavesleep Ar sleep
640 For IEEE 802.11 wireless interfaces, set the desired max powersave sleep
641 time in milliseconds.
642 .It Cm protmode Ar technique
643 For IEEE 802.11 wireless interfaces operating in 11g, use the specified
645 for protecting OFDM frames in a mixed 11b/11g network.
646 The set of valid techniques is
653 Technique names are case insensitive.
654 .It Cm rtsthreshold Ar length
655 For IEEE 802.11 wireless interfaces, set the threshold for which
656 transmitted frames are preceded by transmission of an
662 is the frame size in bytes and must be in the range 1 to 2312.
663 Not all adaptors support setting the RTS threshold.
664 .It Cm txpower Ar power
665 For IEEE 802.11 wireless interfaces, set the power used to transmit frames.
669 is a unitless value in the range 0 to 100 that is interpreted
670 by drivers to derive a device-specific value.
671 Out of range values are truncated.
672 Typically only a few discreet power settings are available and
673 the driver will use the setting closest to the specified value.
674 Not all adaptors support changing the transmit power.
675 .It Cm wepmode Ar mode
676 For IEEE 802.11 wireless interfaces, set the desired WEP mode.
677 Not all adaptors support all modes.
678 The set of valid modes is
685 mode explicitly tells the adaptor to allow association with access
686 points which allow both encrypted and unencrypted traffic.
689 means that the access point must only allow encrypted connections.
692 is generally another name for
694 Modes are case insensitive.
695 .It Cm weptxkey Ar index
696 For IEEE 802.11 wireless interfaces, set the WEP key to be used for
698 .It Cm wepkey Ar key Ns | Ns Ar index : Ns Ar key
699 For IEEE 802.11 wireless interfaces, set the selected WEP key.
702 is not given, key 1 is set.
703 A WEP key will be either 5 or 13
704 characters (40 or 104 bits) depending of the local network and the
705 capabilities of the adaptor.
706 It may be specified either as a plain
707 string or as a string of hexadecimal digits proceeded by
709 For maximum portability, hex keys are recommended;
710 the mapping of text keys to WEP encryption is usually driver-specific.
713 drivers do this mapping differently to
715 A key may be cleared by setting it to
717 If WEP is supported then there are at least four keys.
718 Some adaptors support more than four keys.
719 If that is the case, then the first four keys
720 (1-4) will be the standard temporary keys and any others will be adaptor
721 specific keys such as permanent keys stored in NVRAM.
723 Another way of saying
729 Another way of saying
735 Another way of saying:
737 .Dq Li "wepmode on weptxkey 1 wepkey 1:key wepkey 2:- wepkey 3:- wepkey 4:-" .
744 .Ar n : k1 , k2 , k3 , k4
747 Another way of saying
749 .Dq Li "wepmode on weptxkey n wepkey 1:k1 wepkey 2:k2 wepkey 3:k3 wepkey 4:k4" .
755 Another way of saying
765 utility displays the current configuration for a network interface
766 when no optional parameters are supplied.
767 If a protocol family is specified,
769 will report only the details specific to that protocol family.
771 If the driver does supports the media selection system, the supported
772 media list will be included in the output.
776 flag is passed before an interface name,
778 will display the capability list and all
779 of the supported media for the specified interface.
782 flag is supplied, address lifetime is displayed for IPv6 addresses,
783 as time offset string.
787 flag may be used instead of an interface name.
790 to display information about all interfaces in the system.
793 flag limits this to interfaces that are down, and
795 limits this to interfaces that are up.
796 When no arguments are given,
802 flag may be used to list all available interfaces on the system, with
803 no other additional information.
804 Use of this flag is mutually exclusive
805 with all other flags and commands, except for
807 (only list interfaces that are down)
810 (only list interfaces that are up).
814 flag may be used to list all of the interface cloners available on
815 the system, with no additional information.
816 Use of this flag is mutually exclusive with all other flags and commands.
818 Only the super-user may modify the configuration of a network interface.
820 The media selection system is relatively new and only some drivers support
821 it (or have need for it).
823 Messages indicating the specified interface does not exist, the
824 requested address is unknown, or the user is not privileged and
825 tried to alter an interface's configuration.
827 Basic IPv6 node operation requires a link-local address on each
828 interface configured for IPv6.
829 Normally, such an address is automatically configured by the
830 kernel on each interface added to the system; this behaviour may
831 be disabled by setting the sysctl MIB variable
832 .Va net.inet6.ip6.auto_linklocal
835 If you delete such an address using
837 the kernel may act very oddly.
838 Do this at your own risk.