| blob | b9ce6dc59a586ec50aaea7c1f1af1694b54e4d0b |
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30 .\" @(#)ifconfig.8 8.4 (Berkeley) 6/1/94
31 .\"
32 .Dd August 7, 2009
33 .Dt IFCONFIG 8
34 .Os
35 .Sh NAME
36 .Nm ifconfig
37 .Nd configure network interface parameters
38 .Sh SYNOPSIS
39 .Nm
40 .Op Fl N
41 .Ar interface address_family
42 .Oo
43 .Ar address
44 .Op Ar dest_address
45 .Oc
46 .Op Ar parameters
47 .Nm
48 .Op Fl hLmNvz
49 .Ar interface
50 .Op Ar protocol_family
51 .Nm
52 .Fl a
53 .Op Fl bdhLNmsuvz
54 .Op Ar protocol_family
55 .Nm
56 .Fl l
57 .Op Fl bdsu
58 .Nm
59 .Fl s
60 .Ar interface
61 .Nm
62 .Fl C
63 .Sh DESCRIPTION
64 .Nm
65 is used to assign an address
66 to a network interface and/or configure
67 network interface parameters.
68 .Nm
69 must be used at boot time to define the network address
70 of each interface present on a machine; it may also be used at
71 a later time to redefine an interface's address
72 or other operating parameters.
73 .Pp
74 Available operands for
75 .Nm :
76 .Bl -tag -width Ds
77 .It Ar address
78 For the
79 .Tn DARPA-Internet
80 family,
81 the address is either a host name present in the host name data
82 base,
83 .Xr hosts 5 ,
84 or a
85 .Tn DARPA
86 Internet address expressed in the Internet standard
87 .Dq dot notation .
88 For the Xerox Network Systems(tm) family,
89 addresses are
90 .Ar net:a.b.c.d.e.f ,
91 where
92 .Ar net
93 is the assigned network number
94 .Pq in decimal ,
95 and each of the six bytes of the host number,
96 .Ar a
97 through
98 .Ar f ,
99 are specified in hexadecimal.
100 The host number may be omitted on Ethernet interfaces,
101 which use the hardware physical address,
102 and on interfaces other than the first.
103 For the
104 .Tn ISO
105 family, addresses are specified as a long hexadecimal string,
106 as in the Xerox family.
107 However, two consecutive dots imply a zero
108 byte, and the dots are optional, if the user wishes to
109 .Pq carefully
110 count out long strings of digits in network byte order.
111 .It Ar address_family
112 Specifies the
113 .Ar address_family
114 which affects interpretation of the remaining parameters.
115 Since an interface can receive transmissions in differing protocols
116 with different naming schemes, specifying the address family is recommended.
117 The address or protocol families currently
118 supported are
119 .Dq inet ,
120 .Dq inet6 ,
121 .Dq atalk ,
122 .Dq iso ,
123 and
124 .Dq link .
125 .It Ar interface
126 The
127 .Ar interface
128 parameter is a string of the form
129 .Dq name unit ,
130 for example,
131 .Dq en0
132 .El
133 .Pp
134 The following parameters may be set with
135 .Nm :
136 .Bl -tag -width dest_addressxx
137 .It Cm active
138 This keyword applies when
139 .Nm
140 adds or modifies any link-layer address.
141 It indicates that
142 .Nm
143 should
144 .Dq activate
145 the address.
146 Activation makes an address the default source for transmissions
147 on the interface.
148 You may not delete the active address from an interface.
149 You must activate some other address, first.
150 .It Cm advbase Ar n
151 If the driver is a
152 .Xr carp 4
153 pseudo-device, set the base advertisement interval to
154 .Ar n
155 seconds.
156 This ia an 8-bit number; the default value is 1 second.
157 .It Cm advskew Ar n
158 If the driver is a
159 .Xr carp 4
160 pseudo-device, skew the advertisement interval by
161 .Ar n .
162 This is an 8-bit number; the default value is 0.
163 .Pp
164 Taken together the
165 .Cm advbase
166 indicate how frequently, in seconds, the host will advertise the fact that it
167 considers itself the master of the virtual host.
168 The formula is
169 .Cm advbase
170 +
171 .Pf ( Cm advskew
172 / 256).
173 If the master does not advertise within three times this interval, this host
174 will begin advertising as master.
175 .It Cm alias
176 Establish an additional network address for this interface.
177 This is sometimes useful when changing network numbers, and
178 one wishes to accept packets addressed to the old interface.
179 .It Fl alias
180 Remove the specified network address alias.
181 .It Cm arp
182 Enable the use of the Address Resolution Protocol in mapping
183 between network level addresses and link level addresses
184 .Pq default .
185 This is currently implemented for mapping between
186 .Tn DARPA
187 Internet
188 addresses and Ethernet addresses.
189 .It Fl arp
190 Disable the use of the Address Resolution Protocol.
191 .It Cm anycast
192 .Pq inet6 only
193 Set the IPv6 anycast address bit.
194 .It Fl anycast
195 .Pq inet6 only
196 Clear the IPv6 anycast address bit.
197 .It Cm broadcast Ar mask
198 .Pq Inet only
199 Specify the address to use to represent broadcasts to the
200 network.
201 The default broadcast address is the address with a host part of all 1's.
202 .It Cm carpdev Ar iface
203 If the driver is a
204 .Xr carp 4
205 pseudo-device, attach it to
206 .Ar iface .
207 If not specified, the kernel will attempt to select an interface with
208 a subnet matching that of the carp interface.
209 .It Cm debug
210 Enable driver dependent debugging code; usually, this turns on
211 extra console error logging.
212 .It Fl debug
213 Disable driver dependent debugging code.
214 .It Cm delete
215 Remove the network address specified.
216 This would be used if you incorrectly specified an alias, or it
217 was no longer needed.
218 If you have incorrectly set an NS address having the side effect
219 of specifying the host portion, removing all NS addresses will
220 allow you to respecify the host portion.
221 .Cm delete
222 does not work for IPv6 addresses.
223 Use
224 .Fl alias
225 with explicit IPv6 address instead.
226 .It Ar dest_address
227 Specify the address of the correspondent on the other end
228 of a point to point link.
229 .It Cm down
230 Mark an interface ``down''.
231 When an interface is
232 marked ``down'', the system will not attempt to
233 transmit messages through that interface.
234 If possible, the interface will be reset to disable reception as well.
235 This action does not automatically disable routes using the interface.
236 .It Cm ipdst
237 This is used to specify an Internet host who is willing to receive
238 ip packets encapsulating NS packets bound for a remote network.
239 An apparent point to point link is constructed, and
240 the address specified will be taken as the NS address and network
241 of the destination.
242 IP encapsulation of
243 .Tn CLNP
244 packets is done differently.
245 .It Cm media Ar type
246 Set the media type of the interface to
247 .Ar type .
248 Some interfaces support the mutually exclusive use of one of several
249 different physical media connectors.
250 For example, a 10Mb/s Ethernet
251 interface might support the use of either
252 .Tn AUI
253 or twisted pair connectors.
254 Setting the media type to
255 .Dq 10base5
256 or
257 .Dq AUI
258 would change the currently active connector to the AUI port.
259 Setting it to
260 .Dq 10baseT
261 or
262 .Dq UTP
263 would activate twisted pair.
264 Refer to the interfaces' driver
265 specific man page for a complete list of the available types
266 and the
267 .Xr ifmedia 4
268 manual page for a list of media types.
269 See the
270 .Fl m
271 flag below.
272 .It Cm mediaopt Ar opts
273 Set the specified media options on the interface.
274 .Ar opts
275 is a comma delimited list of options to apply to the interface.
276 Refer to the interfaces' driver specific man page for a complete
277 list of available options.
278 Also see the
279 .Xr ifmedia 4
280 manual page for a list of media options.
281 .It Fl mediaopt Ar opts
282 Disable the specified media options on the interface.
283 .It Cm mode Ar mode
284 If the driver supports the media selection system, set the specified
285 operating mode on the interface to
286 .Ar mode .
287 For IEEE 802.11 wireless interfaces that support multiple operating modes
288 this directive is used to select between 802.11a
289 .Pq Dq 11a ,
290 802.11b
291 .Pq Dq 11b ,
292 and 802.11g
293 .Pq Dq 11g
294 operating modes.
295 .It Cm instance Ar minst
296 Set the media instance to
297 .Ar minst .
298 This is useful for devices which have multiple physical layer interfaces
299 .Pq PHYs .
300 Setting the instance on such devices may not be strictly required
301 by the network interface driver as the driver may take care of this
302 automatically; see the driver's manual page for more information.
303 .It Cm metric Ar n
304 Set the routing metric of the interface to
305 .Ar n ,
306 default 0.
307 The routing metric is used by the routing protocol
308 .Pq Xr routed 8 .
309 Higher metrics have the effect of making a route
310 less favorable; metrics are counted as addition hops
311 to the destination network or host.
312 .It Cm mtu Ar n
313 Set the maximum transmission unit of the interface to
314 .Ar n .
315 Most interfaces don't support this option.
316 .It Cm netmask Ar mask
317 .Pq inet, inet6, and ISO
318 Specify how much of the address to reserve for subdividing
319 networks into sub-networks.
320 The mask includes the network part of the local address
321 and the subnet part, which is taken from the host field of the address.
322 The mask can be specified as a single hexadecimal number
323 with a leading 0x, with a dot-notation Internet address,
324 or with a pseudo-network name listed in the network table
325 .Xr networks 5 .
326 The mask contains 1's for the bit positions in the 32-bit address
327 which are to be used for the network and subnet parts,
328 and 0's for the host part.
329 The mask should contain at least the standard network portion,
330 and the subnet field should be contiguous with the network
331 portion.
332 .Pp
333 For INET and INET6 addresses, the netmask can also be given with
334 slash-notation after the address
335 .Pq e.g 192.168.17.3/24 .
336 .\" see
337 .\" Xr eon 5 .
338 .It Cm nsellength Ar n
339 .Pf ( Tn ISO
340 only)
341 This specifies a trailing number of bytes for a received
342 .Tn NSAP
343 used for local identification, the remaining leading part of which is
344 taken to be the
345 .Tn NET
346 .Pq Network Entity Title .
347 The default value is 1, which is conformant to US
348 .Tn GOSIP .
349 When an ISO address is set in an ifconfig command,
350 it is really the
351 .Tn NSAP
352 which is being specified.
353 For example, in
354 .Tn US GOSIP ,
355 20 hex digits should be
356 specified in the
357 .Tn ISO NSAP
358 to be assigned to the interface.
359 There is some evidence that a number different from 1 may be useful
360 for
361 .Tn AFI
362 37 type addresses.
363 .It Cm state Ar state
364 Explicitly force the
365 .Xr carp 4
366 pseudo-device to enter this state.
367 Valid states are
368 .Ar init ,
369 .Ar backup ,
370 and
371 .Ar master .
372 .It Cm frag Ar threshold
373 .Pq IEEE 802.11 devices only
374 Configure the fragmentation threshold for IEEE 802.11-based wireless
375 network interfaces.
376 .It Cm rts Ar threshold
377 .Pq IEEE 802.11 devices only
378 Configure the RTS/CTS threshold for IEEE 802.11-based wireless
379 network interfaces.
380 This controls the number of bytes used for the RTS/CTS handshake boundary.
381 The
382 .Ar threshold
383 can be any value between 0 and 2347.
384 The default is 2347, which indicates the RTS/CTS mechanism should not be used.
385 .It Cm ssid Ar id
386 .Pq IEEE 802.11 devices only
387 Configure the Service Set Identifier (a.k.a. the network name)
388 for IEEE 802.11-based wireless network interfaces.
389 The
390 .Ar id
391 can either be any text string up to 32 characters in length,
392 or a series of up to 64 hexadecimal digits preceded by
393 .Dq 0x .
394 Setting
395 .Ar id
396 to the empty string allows the interface to connect to any available
397 access point.
398 .It Cm nwid Ar id
399 Synonym for
400 .Dq ssid .
401 .It Cm hidessid
402 .Pq IEEE 802.11 devices only
403 When operating as an access point, do not broadcast the SSID
404 in beacon frames or respond to probe request frames unless
405 they are directed to the ap (i.e., they include the ap's SSID).
406 By default, the SSID is included in beacon frames and
407 undirected probe request frames are answered.
408 .It Fl hidessid
409 .Pq IEEE 802.11 devices only
410 When operating as an access point, broadcast the SSID
411 in beacon frames and answer and respond to undirected probe
412 request frames (default).
413 .It Cm nwkey Ar key
414 .Pq IEEE 802.11 devices only
415 Enable WEP encryption for IEEE 802.11-based wireless network interfaces
416 with the
417 .Ar key .
418 The
419 .Ar key
420 can either be a string, a series of hexadecimal digits preceded by
421 .Dq 0x ,
422 or a set of keys in the form
423 .Ar n:k1,k2,k3,k4 ,
424 where
425 .Ar n
426 specifies which of keys will be used for all transmitted packets,
427 and four keys,
428 .Ar k1
429 through
430 .Ar k4 ,
431 are configured as WEP keys.
432 Note that the order must be match within same network if multiple keys
433 are used.
434 For IEEE 802.11 wireless network, the length of each key is restricted to
435 40 bits, i.e. 5-character string or 10 hexadecimal digits,
436 while the WaveLAN/IEEE Gold cards accept the 104 bits
437 .Pq 13 characters
438 key.
439 .It Cm nwkey Cm persist
440 .Pq IEEE 802.11 devices only
441 Enable WEP encryption for IEEE 802.11-based wireless network interfaces
442 with the persistent key written in the network card.
443 .It Cm nwkey Cm persist: Ns Ar key
444 .Pq IEEE 802.11 devices only
445 Write the
446 .Ar key
447 to the persistent memory of the network card, and
448 enable WEP encryption for IEEE 802.11-based wireless network interfaces
449 with the
450 .Ar key .
451 .It Fl nwkey
452 .Pq IEEE 802.11 devices only
453 Disable WEP encryption for IEEE 802.11-based wireless network interfaces.
454 .It Cm apbridge
455 .Pq IEEE 802.11 devices only
456 When operating as an access point, pass packets between
457 wireless clients directly (default).
458 .It Fl apbridge
459 .Pq IEEE 802.11 devices only
460 When operating as an access point, pass packets through
461 the system so that they can be forwared using some other mechanism.
462 Disabling the internal bridging is useful when traffic
463 is to be processed with packet filtering.
464 .It Cm pass Ar passphrase
465 If the driver is a
466 .Xr carp 4
467 pseudo-device, set the authentication key to
468 .Ar passphrase .
469 There is no passphrase by default
470 .It Cm powersave
471 .Pq IEEE 802.11 devices only
472 Enable 802.11 power saving mode.
473 .It Fl powersave
474 .Pq IEEE 802.11 devices only
475 Disable 802.11 power saving mode.
476 .It Cm powersavesleep Ar duration
477 .Pq IEEE 802.11 devices only
478 Set the receiver sleep duration in milliseconds for 802.11 power saving mode.
479 .It Cm bssid Ar bssid
480 .Pq IEEE 802.11 devices only
481 Set the desired BSSID for IEEE 802.11-based wireless network interfaces.
482 .It Fl bssid
483 .Pq IEEE 802.11 devices only
484 Unset the desired BSSID for IEEE 802.11-based wireless network interfaces.
485 The interface will automatically select a BSSID in this mode, which is
486 the default.
487 .It Cm chan Ar chan
488 .Pq IEEE 802.11 devices only
489 Select the channel
490 .Pq radio frequency
491 to be used for IEEE 802.11-based wireless network interfaces.
492 .It Fl chan
493 .Pq IEEE 802.11 devices only
494 Unset the desired channel to be used
495 for IEEE 802.11-based wireless network interfaces.
496 It doesn't affect the channel to be created for IBSS or hostap mode.
497 .It Cm list scan
498 .Pq IEEE 802.11 devices only
499 Display the access points and/or ad-hoc neighbors
500 located in the vicinity.
501 The
502 .Fl v
503 flag may be used to display long SSIDs.
504 .Fl v
505 also causes received information elements to be displayed symbolicaly.
506 Only the super-user can use this command.
507 .It Cm tunnel Ar src_addr Ns Op Ar ,src_port
508 .Ar dest_addr Ns Op Ar ,dest_port
509 .Pq IP tunnel devices only
510 Configure the physical source and destination address for IP tunnel
511 interfaces, including
512 .Xr gif 4 .
513 The arguments
514 .Ar src_addr
515 and
516 .Ar dest_addr
517 are interpreted as the outer source/destination for the encapsulating
518 IPv4/IPv6 header.
519 .Pp
520 On a
521 .Xr gre 4
522 interface in UDP mode, the arguments
523 .Ar src_port
524 and
525 .Ar dest_port
526 are interpreted as the outer source/destination port for the encapsulating
527 UDP header.
528 .It Cm deletetunnel
529 Unconfigure the physical source and destination address for IP tunnel
530 interfaces previously configured with
531 .Cm tunnel .
532 .It Cm create
533 Create the specified network pseudo-device.
534 .It Cm destroy
535 Destroy the specified network pseudo-device.
536 .It Cm pltime Ar n
537 .Pq inet6 only
538 Set preferred lifetime for the address.
539 .It Cm prefixlen Ar n
540 .Pq inet and inet6 only
541 Effect is similar to
542 .Cm netmask .
543 but you can specify by prefix length by digits.
544 .It Cm deprecated
545 .Pq inet6 only
546 Set the IPv6 deprecated address bit.
547 .It Fl deprecated
548 .Pq inet6 only
549 Clear the IPv6 deprecated address bit.
550 .It Cm tentative
551 .Pq inet6 only
552 Set the IPv6 tentative address bit.
553 .It Fl tentative
554 .Pq inet6 only
555 Clear the IPv6 tentative address bit.
556 .It Cm eui64
557 .Pq inet6 only
558 Fill interface index
559 .Pq lowermost 64bit of an IPv6 address
560 automatically.
561 .It Cm link[0-2]
562 Enable special processing of the link level of the interface.
563 These three options are interface specific in actual effect, however,
564 they are in general used to select special modes of operation.
565 An example
566 of this is to enable SLIP compression, or to select the connector type
567 for some Ethernet cards.
568 Refer to the man page for the specific driver
569 for more information.
570 .It Fl link[0-2]
571 Disable special processing at the link level with the specified interface.
572 .It Cm up
573 Mark an interface ``up''.
574 This may be used to enable an interface after an ``ifconfig down.''
575 It happens automatically when setting the first address on an interface.
576 If the interface was reset when previously marked down,
577 the hardware will be re-initialized.
578 .It Cm vhid Ar n
579 If the driver is a
580 .Xr carp 4
581 pseudo-device, set the virtual host ID to
582 .Ar n .
583 Acceptable values are 1 to 255.
584 .It Cm vlan Ar vid
585 If the interface is a
586 .Xr vlan 4
587 pseudo-interface, set the VLAN identifier to
588 .Ar vid .
589 These are the first 12 bits (0-4095) from a 16-bit integer used
590 to create an 802.1Q VLAN header for packets sent from the
591 .Xr vlan 4
592 interface.
593 Note that
594 .Cm vlan
595 and
596 .Cm vlanif
597 must be set at the same time.
598 .It Cm vlanif Ar iface
599 If the interface is a
600 .Xr vlan 4
601 pseudo-interface, associate the physical interface
602 .Ar iface
603 with it.
604 Packets transmitted through the
605 .Xr vlan 4
606 interface will be diverted to the specified physical interface
607 .Ar iface
608 with 802.1Q VLAN encapsulation.
609 Packets with 802.1Q encapsulation received
610 by the physical interface with the correct VLAN tag will be diverted to the
611 associated
612 .Xr vlan 4
613 pseudo-interface.
614 The VLAN interface is assigned a copy of the physical
615 interface's flags and
616 .Tn Ethernet
617 address.
618 If the
619 .Xr vlan 4
620 interface already has a physical interface associated with it, this command
621 will fail.
622 To change the association to another physical interface, the
623 existing association must be cleared first.
624 Note that
625 .Cm vlanif
626 and
627 .Cm vlan
628 must be set at the same time.
629 .It Cm agrport Ar iface
630 Add
631 .Ar iface
632 to the
633 .Xr agr 4
634 interface.
635 .It Cm -agrport Ar iface
636 Remove
637 .Ar iface
638 from the
639 .Xr agr 4
640 interface.
641 .It Cm vltime Ar n
642 .Pq inet6 only
643 Set valid lifetime for the address.
644 .It Cm ip4csum
645 Shorthand of
646 .Dq ip4csum-tx ip4csum-rx
647 .It Cm -ip4csum
648 Shorthand of
649 .Dq -ip4csum-tx -ip4csum-rx
650 .It Cm tcp4csum
651 Shorthand of
652 .Dq tcp4csum-tx tcp4csum-rx
653 .It Cm -tcp4csum
654 Shorthand of
655 .Dq -tcp4csum-tx -tcp4csum-rx
656 .It Cm udp4csum
657 Shorthand of
658 .Dq udp4csum-tx udp4csum-rx
659 .It Cm -udp4csum
660 Shorthand of
661 .Dq -udp4csum-tx -udp4csum-rx
662 .It Cm tcp6csum
663 Shorthand of
664 .Dq tcp6csum-tx tcp6csum-rx
665 .It Cm -tcp6csum
666 Shorthand of
667 .Dq -tcp6csum-tx -tcp6csum-rx
668 .It Cm udp6csum
669 Shorthand of
670 .Dq udp6csum-tx udp6csum-rx
671 .It Cm -udp6csum
672 Shorthand of
673 .Dq -udp6csum-tx -udp6csum-rx
674 .It Cm ip4csum-tx
675 Enable hardware-assisted IPv4 header checksums for the out-bound direction.
676 .It Cm -ip4csum-tx
677 Disable hardware-assisted IPv4 header checksums for the out-bound direction.
678 .It Cm ip4csum-rx
679 Enable hardware-assisted IPv4 header checksums for the in-bound direction.
680 .It Cm -ip4csum-rx
681 Disable hardware-assisted IPv4 header checksums for the in-bound direction.
682 .It Cm tcp4csum-tx
683 Enable hardware-assisted TCP/IPv4 checksums for the out-bound direction.
684 .It Cm -tcp4csum-tx
685 Disable hardware-assisted TCP/IPv4 checksums for the out-bound direction.
686 .It Cm tcp4csum-rx
687 Enable hardware-assisted TCP/IPv4 checksums for the in-bound direction.
688 .It Cm -tcp4csum-rx
689 Disable hardware-assisted TCP/IPv4 checksums for the in-bound direction.
690 .It Cm udp4csum-tx
691 Enable hardware-assisted UDP/IPv4 checksums for the out-bound direction.
692 .It Cm -udp4csum-tx
693 Disable hardware-assisted UDP/IPv4 checksums for the out-bound direction.
694 .It Cm udp4csum-rx
695 Enable hardware-assisted UDP/IPv4 checksums for the in-bound direction.
696 .It Cm -udp4csum-rx
697 Disable hardware-assisted UDP/IPv4 checksums for the in-bound direction.
698 .It Cm tcp6csum-tx
699 Enable hardware-assisted TCP/IPv6 checksums for the out-bound direction.
700 .It Cm -tcp6csum-tx
701 Disable hardware-assisted TCP/IPv6 checksums for the out-bound direction.
702 .It Cm tcp6csum-rx
703 Enable hardware-assisted TCP/IPv6 checksums for the in-bound direction.
704 .It Cm -tcp6csum-rx
705 Disable hardware-assisted TCP/IPv6 checksums for the in-bound direction.
706 .It Cm udp6csum-tx
707 Enable hardware-assisted UDP/IPv6 checksums for the out-bound direction.
708 .It Cm -udp6csum-tx
709 Disable hardware-assisted UDP/IPv6 checksums for the out-bound direction.
710 .It Cm udp6csum-rx
711 Enable hardware-assisted UDP/IPv6 checksums for the in-bound direction.
712 .It Cm -udp6csum-rx
713 Disable hardware-assisted UDP/IPv6 checksums for the in-bound direction.
714 .It Cm tso4
715 Enable hardware-assisted TCP/IPv4 segmentation on interfaces that
716 support it.
717 .It Cm -tso4
718 Disable hardware-assisted TCP/IPv4 segmentation on interfaces that
719 support it.
720 .It Cm tso6
721 Enable hardware-assisted TCP/IPv6 segmentation on interfaces that
722 support it.
723 .It Cm -tso6
724 Disable hardware-assisted TCP/IPv6 segmentation on interfaces that
725 support it.
726 .It Cm maxupd Ar n
727 If the driver is a
728 .Xr pfsync 4
729 pseudo-device, indicate the maximum number
730 of updates for a single state which can be collapsed into one.
731 This is an 8-bit number; the default value is 128.
732 .It Cm syncdev Ar iface
733 If the driver is a
734 .Xr pfsync 4
735 pseudo-device, use the specified interface
736 to send and receive pfsync state synchronisation messages.
737 .It Fl syncdev
738 If the driver is a
739 .Xr pfsync 4
740 pseudo-device, stop sending pfsync state
741 synchronisation messages over the network.
742 .It Cm syncpeer Ar peer_address
743 If the driver is a
744 .Xr pfsync 4
745 pseudo-device, make the pfsync link point-to-point rather than using
746 multicast to broadcast the state synchronisation messages.
747 The peer_address is the IP address of the other host taking part in
748 the pfsync cluster.
749 With this option,
750 .Xr pfsync 4
751 traffic can be protected using
752 .Xr ipsec 4 .
753 .It Fl syncpeer
754 If the driver is a
755 .Xr pfsync 4
756 pseudo-device, broadcast the packets using multicast.
757 .El
758 .Pp
759 .Nm
760 displays the current configuration for a network interface
761 when no optional parameters are supplied.
762 If a protocol family is specified,
763 .Nm
764 will report only the details specific to that protocol
765 family.
766 .Pp
767 If the
768 .Fl s
769 flag is passed before an interface name,
770 .Nm
771 will attempt to query the interface for its media status.
772 If the
773 interface supports reporting media status, and it reports that it does
774 not appear to be connected to a network,
775 .Nm
776 will exit with status of 1
777 .Pq false ;
778 otherwise, it will exit with a
779 zero
780 .Pq true
781 exit status.
782 Not all interface drivers support media
783 status reporting.
784 .Pp
785 If the
786 .Fl m
787 flag is passed before an interface name,
788 .Nm
789 will display all of the supported media for the specified interface.
790 If the
791 .Fl L
792 flag is supplied, address lifetime is displayed for IPv6 addresses,
793 as time offset string.
794 .Pp
795 Optionally, the
796 .Fl a
797 flag may be used instead of an interface name.
798 This flag instructs
799 .Nm
800 to display information about all interfaces in the system.
801 .Fl d
802 limits this to interfaces that are down,
803 .Fl u
804 limits this to interfaces that are up,
805 .Fl b
806 limits this to broadcast interfaces, and
807 .Fl s
808 omits interfaces which appear not to be connected to a network.
809 .Pp
810 The
811 .Fl l
812 flag may be used to list all available interfaces on the system, with
813 no other additional information.
814 Use of this flag is mutually exclusive
815 with all other flags and commands, except for
816 .Fl d
817 .Pq only list interfaces that are down ,
818 .Fl u
819 .Pq only list interfaces that are up ,
820 .Fl s
821 .Pq only list interfaces that may be connected ,
822 .Fl b
823 .Pq only list broadcast interfaces .
824 .Pp
825 The
826 .Fl C
827 flag may be used to list all of the interface cloners available on
828 the system, with no additional information.
829 Use of this flag is
830 mutually exclusive with all other flags and commands.
831 .Pp
832 The
833 .Fl v
834 flag prints statistics on packets sent and received on the given
835 interface.
836 If
837 .Fl h
838 is used in conjunction with
839 .Fl v ,
840 the byte statistics will be printed in "human-readable" format.
841 The
842 .Fl z
843 flag is identical to the
844 .Fl v
845 flag except that it zeros the interface input and output statistics
846 after printing them.
847 .Pp
848 The
849 .Fl N
850 flag is just the opposite of the
851 .Fl n
852 flag in
853 .Xr netstat 1
854 or in
855 .Xr route 8 :
856 it tells
857 .Nm
858 to try to resolve numbers to hostnames or to service names.
859 The default
860 .Nm
861 behavior is to print numbers instead of names.
862 .Pp
863 Only the super-user may modify the configuration of a network interface.
864 .Sh EXAMPLES
865 Add a link-layer (MAC) address to an Ethernet:
866 .Pp
867 .Ic ifconfig sip0 link 00:11:22:33:44:55
868 .Pp
869 Add and activate a link-layer (MAC) address:
870 .Pp
871 .Ic ifconfig sip0 link 00:11:22:33:44:55 active
872 .Sh DIAGNOSTICS
873 Messages indicating the specified interface does not exist, the
874 requested address is unknown, or the user is not privileged and
875 tried to alter an interface's configuration.
876 .Sh SEE ALSO
877 .Xr netstat 1 ,
878 .Xr agr 4 ,
879 .Xr carp 4 ,
880 .Xr ifmedia 4 ,
881 .Xr netintro 4 ,
882 .Xr pfsync 4 ,
883 .Xr vlan 4 ,
884 .Xr ifconfig.if 5 ,
885 .\" .Xr eon 5 ,
886 .Xr rc 8 ,
887 .Xr routed 8
888 .Sh HISTORY
889 The
890 .Nm
891 command appeared in
892 .Bx 4.2 .