1.\" Copyright (c) 1983, 1991, 1993 2.\" The Regents of the University of California. All rights reserved. 3.\" 4.\" Redistribution and use in source and binary forms, with or without 5.\" modification, are permitted provided that the following conditions 6.\" are met: 7.\" 1. Redistributions of source code must retain the above copyright 8.\" notice, this list of conditions and the following disclaimer. 9.\" 2. Redistributions in binary form must reproduce the above copyright 10.\" notice, this list of conditions and the following disclaimer in the 11.\" documentation and/or other materials provided with the distribution. 12.\" 3. Neither the name of the University nor the names of its contributors 13.\" may be used to endorse or promote products derived from this software 14.\" without specific prior written permission. 15.\" 16.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 17.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 18.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 19.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 20.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 21.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 22.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 23.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 24.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 25.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 26.\" SUCH DAMAGE. 27.\" 28.\" From: @(#)ifconfig.8 8.3 (Berkeley) 1/5/94 29.\" $FreeBSD: src/sbin/ifconfig/ifconfig.8,v 1.124 2006/10/10 09:44:08 ru Exp $ 30.\" 31.Dd June 26, 2020 32.Dt IFCONFIG 8 33.Os 34.Sh NAME 35.Nm ifconfig 36.Nd configure network interface parameters 37.Sh SYNOPSIS 38.Nm 39.Op Fl f Ar type:format Ns Op Ar ,type:format 40.Op Fl L 41.Op Fl k 42.Op Fl m 43.Op Fl n 44.Ar interface 45.Op Cm create 46.Op Ar address_family 47.Oo 48.Ar address 49.Op Ar dest_address 50.Oc 51.Op Ar parameters 52.Nm 53.Op Fl n 54.Ar interface 55.Cm destroy 56.Nm 57.Fl a 58.Op Fl G Ar nogroup 59.Op Fl L 60.Oo 61.Fl d | 62.Fl u 63.Oc 64.Op Fl g Ar matchgroup 65.Op Fl m 66.Op Fl v 67.Op Ar address_family 68.Nm 69.Fl l 70.Oo 71.Fl d | 72.Fl u 73.Oc 74.Op Ar address_family 75.Nm 76.Op Fl L 77.Oo 78.Fl d | 79.Fl u 80.Oc 81.Op Fl k 82.Op Fl m 83.Op Fl v 84.Op Fl C 85.Nm 86.Op Fl g Ar groupname 87.Sh DESCRIPTION 88The 89.Nm 90utility is used to assign an address 91to a network interface and/or configure 92network interface parameters. 93The 94.Nm 95utility must be used at boot time to define the network address 96of each interface present on a machine; it may also be used at 97a later time to redefine an interface's address 98or other operating parameters. 99.Pp 100The following options are available: 101.Bl -tag -width indent 102.It Ar address 103For the 104.Tn DARPA Ns -Internet 105family, 106the address is either a host name present in the host name data 107base, 108.Xr hosts 5 , 109or a 110.Tn DARPA 111Internet address expressed in the Internet standard 112.Dq dot notation . 113.Pp 114It is also possible to use the CIDR notation (also known as the 115slash notation) to include the netmask. 116That is, one can specify an address like 117.Li 192.168.0.1/16 . 118.Pp 119For 120.Dq inet6 121family, it is also possible to specify the prefix length using the slash 122notation, like 123.Li ::1/128 . 124See the 125.Cm prefixlen 126parameter below for more information. 127.\" For the Xerox Network Systems(tm) family, 128.\" addresses are 129.\" .Ar net:a.b.c.d.e.f , 130.\" where 131.\" .Ar net 132.\" is the assigned network number (in decimal), 133.\" and each of the six bytes of the host number, 134.\" .Ar a 135.\" through 136.\" .Ar f , 137.\" are specified in hexadecimal. 138.\" The host number may be omitted on IEEE 802 protocol 139.\" (Ethernet, FDDI, and Token Ring) interfaces, 140.\" which use the hardware physical address, 141.\" and on interfaces other than the first. 142.\" For the 143.\" .Tn ISO 144.\" family, addresses are specified as a long hexadecimal string, 145.\" as in the Xerox family. 146.\" However, two consecutive dots imply a zero 147.\" byte, and the dots are optional, if the user wishes to (carefully) 148.\" count out long strings of digits in network byte order. 149.Pp 150The link-level 151.Pq Dq link 152address 153is specified as a series of colon-separated hex digits. 154This can be used to 155e.g.\& set a new MAC address on an Ethernet interface, though the 156mechanism used is not Ethernet-specific. 157If the interface is already 158up when this option is used, it will be briefly brought down and 159then brought back up again in order to ensure that the receive 160filter in the underlying Ethernet hardware is properly reprogrammed. 161.It Ar address_family 162Specify the 163address family 164which affects interpretation of the remaining parameters. 165Since an interface can receive transmissions in differing protocols 166with different naming schemes, specifying the address family is recommended. 167The address or protocol families currently 168supported are 169.Dq inet , 170.Dq inet6 , 171.Dq atalk , 172and 173.Dq link . 174The default is 175.Dq inet . 176.Dq ether 177and 178.Dq lladdr 179are synonyms for 180.Dq link . 181.It Ar dest_address 182Specify the address of the correspondent on the other end 183of a point to point link. 184.It Ar interface 185This 186parameter is a string of the form 187.Dq name unit , 188for example, 189.Dq Li ed0 . 190.It Ar groupname 191List the interfaces in the given group. 192.El 193.Pp 194The output format of 195.Nm 196can be controlled with the 197.Fl f 198option or the 199.Ev IFCONFIG_FORMAT 200environment variable. 201The format is specified as a comma-separated list of 202.Sy type:format 203pairs. 204The supported 205.Sy type 206and its associated 207.Sy format 208strings are: 209.Bl -tag -width indent 210.It Sy addr 211Adjust the display of inet and inet6 addresses: 212.Bl -tag -width default 213.It Sy default 214Display inet and inet6 addresses in the default format, i.e., 215.Sy numeric . 216.It Sy fqdn 217Display inet and inet6 addresses as fully qualified domain names 218.Pq FQDN . 219.It Sy host 220Display inet and inet6 addresses as unqualified hostnames. 221.It Sy numeric 222Display inet and inet6 addresses in numeric format. 223.El 224.It Sy ether 225Adjust the display of link-level Ethernet (MAC) addresses: 226.Bl -tag -width default 227.It Sy colon 228Separate address segments with a colon. 229.It Sy dash 230Separate address segments with a dash. 231.It Sy default 232Display Ethernet addresses in the default format, i.e., 233.Sy colon . 234.El 235.It Sy inet 236Adjust the display of inet address subnet masks: 237.Bl -tag -width default 238.It Sy cidr 239Display subnet masks in CIDR notation, for example: 240.br 24110.0.0.0/8 or 203.0.113.224/26 242.It Sy default 243Display subnet masks in the default format, i.e., 244.Sy hex . 245.It Sy dotted 246Display subnet masks in dotted quad notation, for example: 247.br 248255.255.0.0, 255.255.255.192 249.It Sy hex 250Display subnet masks in hexidecimal, for example: 251.br 2520xffff0000, 0xffffffc0 253.El 254.It Sy inet6 255Adjust the display of inet6 address prefixes (subnet masks): 256.Bl -tag -width default 257.It Sy cidr 258Display subnet prefix in CIDR notation, for example: 259.br 260::1/128, fe80::1%lo0/64 261.It Sy default 262Display subnet prefix in the default format, i.e., 263.Sy numeric 264.It Sy numeric 265Display subnet prefix in integer format, for example: 266.br 267prefixlen 64 268.El 269.El 270.Pp 271The following parameters may be set with 272.Nm : 273.Bl -tag -width indent 274.It Cm add 275Another name for the 276.Cm alias 277parameter. 278Introduced for compatibility 279with 280.Bsx . 281.It Cm alias 282Establish an additional network address for this interface. 283This is sometimes useful when changing network numbers, and 284one wishes to accept packets addressed to the old interface. 285If the address is on the same subnet as the first network address 286for this interface, a non-conflicting netmask must be given. 287Usually 288.Li 0xffffffff 289is most appropriate. 290.It Fl alias 291Remove the network address specified. 292This would be used if you incorrectly specified an alias, or it 293was no longer needed. 294If you have incorrectly set an NS address having the side effect 295of specifying the host portion, removing all NS addresses will 296allow you to respecify the host portion. 297.It Cm anycast 298(Inet6 only.) 299Specify that the address configured is an anycast address. 300Based on the current specification, 301only routers may configure anycast addresses. 302Anycast address will not be used as source address of any of outgoing 303IPv6 packets. 304.It Cm arp 305Enable the use of the Address Resolution Protocol 306.Pq Xr arp 4 307in mapping 308between network level addresses and link level addresses (default). 309This is currently implemented for mapping between 310.Tn DARPA 311Internet 312addresses and 313.Tn IEEE 314802 48-bit MAC addresses (Ethernet, FDDI, and Token Ring addresses). 315.It Fl arp 316Disable the use of the Address Resolution Protocol 317.Pq Xr arp 4 . 318.It Cm staticarp 319If the Address Resolution Protocol is enabled, 320the host will only reply to requests for its addresses, 321and will never send any requests. 322.It Fl staticarp 323If the Address Resolution Protocol is enabled, 324the host will perform normally, 325sending out requests and listening for replies. 326.It Cm broadcast 327(Inet only.) 328Specify the address to use to represent broadcasts to the 329network. 330The default broadcast address is the address with a host part of all 1's. 331.It Cm debug 332Enable driver dependent debugging code; usually, this turns on 333extra console error logging. 334.It Fl debug 335Disable driver dependent debugging code. 336.It Cm promisc 337Put interface into permanently promiscuous mode. 338.It Fl promisc 339Disable permanently promiscuous mode. 340.It Cm delete 341Another name for the 342.Fl alias 343parameter. 344.It Cm down 345Mark an interface 346.Dq down . 347When an interface is marked 348.Dq down , 349the system will not attempt to 350transmit messages through that interface. 351If possible, the interface will be reset to disable reception as well. 352This action does not automatically disable routes using the interface. 353.It Cm group Ar group-name 354Assign the interface to a 355.Dq group . 356Any interface can be in multiple groups. 357.Pp 358Cloned interfaces are members of their interface family group by default. 359For example, a PPP interface such as 360.Em ppp0 361is a member of the PPP interface family group, 362.Em ppp . 363.\" The interface(s) that the default route(s) point to are members of the 364.\" .Em egress 365.\" interface group. 366.It Cm -group Ar group-name 367Remove the interface from the given 368.Dq group . 369.It Cm eui64 370(Inet6 only.) 371Fill interface index 372(lowermost 64bit of an IPv6 address) 373automatically. 374.It Cm media Ar type 375If the driver supports the media selection system, set the media type 376of the interface to 377.Ar type . 378Some interfaces support the mutually exclusive use of one of several 379different physical media connectors. 380For example, a 10Mbit/s Ethernet 381interface might support the use of either 382.Tn AUI 383or twisted pair connectors. 384Setting the media type to 385.Cm 10base5/AUI 386would change the currently active connector to the AUI port. 387Setting it to 388.Cm 10baseT/UTP 389would activate twisted pair. 390Refer to the interfaces' driver 391specific documentation or man page for a complete list of the 392available types. 393.It Cm mediaopt Ar opts 394If the driver supports the media selection system, set the specified 395media options on the interface. 396The 397.Ar opts 398argument 399is a comma delimited list of options to apply to the interface. 400Refer to the interfaces' driver specific man page for a complete 401list of available options. 402.It Fl mediaopt Ar opts 403If the driver supports the media selection system, disable the 404specified media options on the interface. 405.It Cm mode Ar mode 406If the driver supports the media selection system, set the specified 407operating mode on the interface to 408.Ar mode . 409For IEEE 802.11 wireless interfaces that support multiple operating modes 410this directive is used to select between 802.11a 411.Pq Cm 11a , 412802.11b 413.Pq Cm 11b , 414and 802.11g 415.Pq Cm 11g 416operating modes. 417.It Cm name Ar name 418Set the interface name to 419.Ar name . 420.It Cm rss 421If the driver supports receive side scaling, 422enable receive side scaling on the interface. 423.It Fl rss 424If the driver supports receive side scaling, 425disable receive side scaling on the interface. 426.It Cm rxcsum , txcsum 427If the driver supports user-configurable checksum offloading, 428enable receive (or transmit) checksum offloading on the interface. 429Some drivers may not be able to enable these flags independently 430of each other, so setting one may also set the other. 431The driver will offload as much checksum work as it can reliably 432support, the exact level of offloading varies between drivers. 433.It Fl rxcsum , txcsum 434If the driver supports user-configurable checksum offloading, 435disable receive (or transmit) checksum offloading on the interface. 436These settings may not always be independent of each other. 437.It Cm tso 438If the driver supports TCP segmentation offloading, 439enable TCP segmentation offloading on the interface. 440.It Fl tso 441If the driver supports TCP segmentation offloading, 442disable TCP segmentation offloading on the interface. 443.It Cm vlanmtu , vlanhwtag 444If the driver offers user-configurable VLAN support, enable 445reception of extended frames or tag processing in hardware, 446respectively. 447Note that this must be issued on a physical interface associated with 448.Xr vlan 4 , 449not on a 450.Xr vlan 4 451interface itself. 452.It Fl vlanmtu , vlanhwtag 453If the driver offers user-configurable VLAN support, disable 454reception of extended frames or tag processing in hardware, 455respectively. 456.It Cm pollcpu Ar cpu 457Deprecated, use polling or npolling instead. 458.It Cm polling , npolling 459Turn on 460.Xr polling 4 461feature and disable interrupts on the interface, if the driver supports 462this mode. 463.It Fl polling , npolling 464Turn off 465.Xr polling 4 466feature and enable interrupt mode on the interface. 467.It Cm create 468Create the specified network pseudo-device. 469If the interface is given without a unit number, try to create a new 470device with an arbitrary unit number. 471If creation of an arbitrary device is successful, the new device name is 472printed to standard output unless the interface is renamed or destroyed 473in the same 474.Nm 475invocation. 476.It Cm destroy 477Destroy the specified network pseudo-device. 478.It Cm plumb 479Another name for the 480.Cm create 481parameter. 482Included for 483.Tn Solaris 484compatibility. 485.It Cm unplumb 486Another name for the 487.Cm destroy 488parameter. 489Included for 490.Tn Solaris 491compatibility. 492.It Cm metric Ar n 493Set the routing metric of the interface to 494.Ar n , 495default 0. 496The routing metric is used by the routing protocol 497.Pq Xr routed 8 . 498Higher metrics have the effect of making a route 499less favorable; metrics are counted as additional hops 500to the destination network or host. 501.It Cm mtu Ar n 502Set the maximum transmission unit of the interface to 503.Ar n , 504default is interface specific. 505The MTU is used to limit the size of packets that are transmitted on an 506interface. 507Not all interfaces support setting the MTU, and some interfaces have 508range restrictions. 509.It Cm tsolen Ar n 510Set the maximum amount of data 511that TCP segmentation offloading is allowed to aggregate to 512.Ar n , 513the default value is interface specific. 514This setting only takes effect on interfaces 515that support TCP segmentation offloading. 516.It Cm netmask Ar mask 517.\" (Inet and ISO.) 518(Inet only.) 519Specify how much of the address to reserve for subdividing 520networks into sub-networks. 521The mask includes the network part of the local address 522and the subnet part, which is taken from the host field of the address. 523The mask can be specified as a single hexadecimal number 524with a leading 525.Ql 0x , 526with a dot-notation Internet address, 527or with a pseudo-network name listed in the network table 528.Xr networks 5 . 529The mask contains 1's for the bit positions in the 32-bit address 530which are to be used for the network and subnet parts, 531and 0's for the host part. 532The mask should contain at least the standard network portion, 533and the subnet field should be contiguous with the network 534portion. 535.Pp 536The netmask can also be specified in CIDR notation after the address. 537See the 538.Ar address 539option above for more information. 540.It Cm autoconf 541(Inet6 only.) 542Enable autoconfiguration. 543.It Fl autoconf 544Disable autoconfiguration. 545.It Cm pltime Ar n 546(Inet6 only.) 547Set preferred lifetime for the address. 548.It Cm vltime Ar n 549(Inet6 only.) 550Set valid lifetime for the address. 551.It Cm prefixlen Ar len 552(Inet6 only.) 553Specify that 554.Ar len 555bits are reserved for subdividing networks into sub-networks. 556The 557.Ar len 558must be integer, and for syntactical reason it must be between 0 to 128. 559It is almost always 64 under the current IPv6 assignment rule. 560If the parameter is omitted, 64 is used. 561.Pp 562The prefix can also be specified using the slash notation after the address. 563See the 564.Ar address 565option above for more information. 566.It Cm deprecated 567(Inet6 only.) 568Set the IPv6 deprecated address bit. 569.It Fl deprecated 570(Inet6 only.) 571Clear the IPv6 deprecated address bit. 572.It Cm tentative 573(Inet6 only.) 574Set the IPv6 tentative address bit. 575.It Fl tentative 576(Inet6 only.) 577Clear the IPv6 tentative address bit. 578.\" see 579.\" Xr eon 5 . 580.\" .It Cm nsellength Ar n 581.\" .Pf ( Tn ISO 582.\" only) 583.\" This specifies a trailing number of bytes for a received 584.\" .Tn NSAP 585.\" used for local identification, the remaining leading part of which is 586.\" taken to be the 587.\" .Tn NET 588.\" (Network Entity Title). 589.\" The default value is 1, which is conformant to US 590.\" .Tn GOSIP . 591.\" When an ISO address is set in an ifconfig command, 592.\" it is really the 593.\" .Tn NSAP 594.\" which is being specified. 595.\" For example, in 596.\" .Tn US GOSIP , 597.\" 20 hex digits should be 598.\" specified in the 599.\" .Tn ISO NSAP 600.\" to be assigned to the interface. 601.\" There is some evidence that a number different from 1 may be useful 602.\" for 603.\" .Tn AFI 604.\" 37 type addresses. 605.It Cm range Ar netrange 606Under appletalk, set the interface to respond to a 607.Ar netrange 608of the form 609.Ar startnet Ns - Ns Ar endnet . 610Appletalk uses this scheme instead of 611netmasks though 612.Dx 613implements it internally as a set of netmasks. 614.It Cm remove 615Another name for the 616.Fl alias 617parameter. 618Introduced for compatibility 619with 620.Bsx . 621.It Cm phase 622The argument following this specifies the version (phase) of the 623Appletalk network attached to the interface. 624Values of 1 or 2 are permitted. 625.Sm off 626.It Cm link Op Cm 0 No - Cm 2 627.Sm on 628Enable special processing of the link level of the interface. 629These three options are interface specific in actual effect, however, 630they are in general used to select special modes of operation. 631An example 632of this is to enable SLIP compression, or to select the connector type 633for some Ethernet cards. 634Refer to the man page for the specific driver 635for more information. 636.Sm off 637.It Fl link Op Cm 0 No - Cm 2 638.Sm on 639Disable special processing at the link level with the specified interface. 640.It Cm compress 641Another name for the 642.Cm link0 643parameter. 644.It Cm normal 645Another name for the 646.Fl link0 647parameter. 648.It Cm noicmp 649Another name for the 650.Cm link1 651parameter. 652.It Cm monitor 653Put the interface in monitor mode. 654No packets are transmitted, and received packets are discarded after 655.Xr bpf 4 656processing. 657.It Fl monitor 658Take the interface out of monitor mode. 659.It Cm up 660Mark an interface 661.Dq up . 662This may be used to enable an interface after an 663.Dq Nm Cm down . 664It happens automatically when setting the first address on an interface. 665If the interface was reset when previously marked down, 666the hardware will be re-initialized. 667.El 668.Pp 669The following parameters are specific to cloning 670IEEE 802.11 wireless interfaces with the 671.Cm create 672request: 673.Bl -tag -width indent 674.It Cm wlandev Ar device 675Use 676.Ar device 677as the parent for the cloned device. 678.It Cm wlanmode Ar mode 679Specify the operating mode for this cloned device. 680.Ar mode 681is one of 682.Cm sta , 683.Cm ahdemo 684(or 685.Cm adhoc-demo ), 686.Cm ibss , 687(or 688.Cm adhoc ), 689.Cm ap , 690(or 691.Cm hostap ), 692.Cm wds , 693.Cm tdma , 694.Cm mesh , 695and 696.Cm monitor . 697The operating mode of a cloned interface cannot be changed. 698The 699.Cm tdma 700mode is actually implemented as an 701.Cm adhoc-demo 702interface with special properties. 703.It Cm wlanbssid Ar bssid 704The 802.11 mac address to use for the bssid. 705This must be specified at create time for a legacy 706.Cm wds 707device. 708.It Cm wlanaddr Ar address 709The local mac address. 710If this is not specified then a mac address will automatically be assigned 711to the cloned device. 712Typically this address is the same as the address of the parent device 713but if the 714.Cm bssid 715parameter is specified then the driver will craft a unique address for 716the device (if supported). 717.It Cm wdslegacy 718Mark a 719.Cm wds 720device as operating in ``legacy mode''. 721Legacy 722.Cm wds 723devices have a fixed peer relationship and do not, for example, roam 724if their peer stops communicating. 725For completeness a Dynamic WDS (DWDS) interface may marked as 726.Fl wdslegacy . 727.It Cm bssid 728Request a unique local mac address for the cloned device. 729This is only possible if the device supports multiple mac addresses. 730To force use of the parent's mac address use 731.Fl bssid . 732.It Cm beacons 733Mark the cloned interface as depending on hardware support to 734track received beacons. 735To have beacons tracked in software use 736.Fl beacons . 737For 738.Cm hostap 739mode 740.Fl beacons 741can also be used to indicate no beacons should 742be transmitted; this can be useful when creating a WDS configuration but 743.Cm wds 744interfaces can only be created as companions to an access point. 745.El 746.Pp 747The following parameters are specific to IEEE 802.11 wireless interfaces 748cloned with a 749.Cm create 750operation: 751.Bl -tag -width indent 752.It Cm ampdu 753Enable sending and receiving AMPDU frames when using 802.11n (default). 754The 802.11n specification states a compliant station must be capable 755of receiving AMPDU frames but transmission is optional. 756Use 757.Fl ampdu 758to disable all use of AMPDU with 802.11n. 759For testing and/or to work around interoperability problems one can use 760.Cm ampdutx 761and 762.Cm ampdurx 763to control use of AMPDU in one direction. 764.It Cm ampdudensity Ar density 765Set the AMPDU density parameter used when operating with 802.11n. 766This parameter controls the inter-packet gap for AMPDU frames. 767The sending device normally controls this setting but a receiving station 768may request wider gaps. 769Legal values for 770.Ar density 771are 0, .25, .5, 1, 2, 4, 8, and 16 (microseconds). 772A value of 773.Cm - 774is treated the same as 0. 775.It Cm ampdulimit Ar limit 776Set the limit on packet size for receiving AMPDU frames when operating 777with 802.11n. 778Legal values for 779.Ar limit 780are 8192, 16384, 32768, and 65536 but one can also specify 781just the unique prefix: 8, 16, 32, 64. 782Note the sender may limit the size of AMPDU frames to be less 783than the maximum specified by the receiving station. 784.It Cm amsdu 785Enable sending and receiving AMSDU frames when using 802.11n. 786By default AMSDU is received but not transmitted. 787Use 788.Fl amsdu 789to disable all use of AMSDU with 802.11n. 790For testing and/or to work around interoperability problems one can use 791.Cm amsdutx 792and 793.Cm amsdurx 794to control use of AMSDU in one direction. 795.It Cm amsdulimit Ar limit 796Set the limit on packet size for sending and receiving AMSDU frames 797when operating with 802.11n. 798Legal values for 799.Ar limit 800are 7935 and 3839 (bytes). 801Note the sender may limit the size of AMSDU frames to be less 802than the maximum specified by the receiving station. 803Note also that devices are not required to support the 7935 limit, 804only 3839 is required by the specification and the larger value 805may require more memory to be dedicated to support functionality 806that is rarely used. 807.It Cm apbridge 808When operating as an access point, pass packets between 809wireless clients directly (default). 810To instead let them pass up through the 811system and be forwarded using some other mechanism, use 812.Fl apbridge . 813Disabling the internal bridging 814is useful when traffic is to be processed with 815packet filtering. 816.It Cm authmode Ar mode 817Set the desired authentication mode in infrastructure mode. 818Not all adapters support all modes. 819The set of 820valid modes is 821.Cm none , open , shared 822(shared key), 823.Cm 8021x 824(IEEE 802.1x), 825and 826.Cm wpa 827(IEEE WPA/WPA2/802.11i). 828The 829.Cm 8021x 830and 831.Cm wpa 832modes are only useful when using an authentication service 833(a supplicant for client operation or an authenticator when 834operating as an access point). 835Modes are case insensitive. 836.It Cm bgscan 837Enable background scanning when operating as a station. 838Background scanning is a technique whereby a station associated to 839an access point will temporarily leave the channel to scan for 840neighboring stations. 841This allows a station to maintain a cache of nearby access points 842so that roaming between access points can be done without 843a lengthy scan operation. 844Background scanning is done only when a station is not busy and 845any outbound traffic will cancel a scan operation. 846Background scanning should never cause packets to be lost though 847there may be some small latency if outbound traffic interrupts a 848scan operation. 849By default background scanning is enabled if the device is capable. 850To disable background scanning, use 851.Fl bgscan . 852Background scanning is controlled by the 853.Cm bgscanidle 854and 855.Cm bgscanintvl 856parameters. 857Background scanning must be enabled for roaming; this is an artifact 858of the current implementation and may not be required in the future. 859.It Cm bgscanidle Ar idletime 860Set the minimum time a station must be idle (not transmitting or 861receiving frames) before a background scan is initiated. 862The 863.Ar idletime 864parameter is specified in milliseconds. 865By default a station must be idle at least 250 milliseconds before 866a background scan is initiated. 867The idle time may not be set to less than 100 milliseconds. 868.It Cm bgscanintvl Ar interval 869Set the interval at which background scanning is attempted. 870The 871.Ar interval 872parameter is specified in seconds. 873By default a background scan is considered every 300 seconds (5 minutes). 874The 875.Ar interval 876may not be set to less than 15 seconds. 877.It Cm bintval Ar interval 878Set the interval at which beacon frames are sent when operating in 879ad-hoc or ap mode. 880The 881.Ar interval 882parameter is specified in TU's (1024 usecs). 883By default beacon frames are transmitted every 100 TU's. 884.It Cm bmissthreshold Ar count 885Set the number of consecutive missed beacons at which the station 886will attempt to roam (i.e., search for a new access point). 887The 888.Ar count 889parameter must be in the range 1 to 255; though the 890upper bound may be reduced according to device capabilities. 891The default threshold is 7 consecutive missed beacons; but 892this may be overridden by the device driver. 893Another name for the 894.Cm bmissthreshold 895parameter is 896.Cm bmiss . 897.It Cm bssid Ar address 898Specify the MAC address of the access point to use when operating 899as a station in a BSS network. 900This overrides any automatic selection done by the system. 901To disable a previously selected access point, supply 902.Cm any , none , 903or 904.Cm - 905for the address. 906This option is useful when more than one access point uses the same SSID. 907Another name for the 908.Cm bssid 909parameter is 910.Cm ap . 911.It Cm burst 912Enable packet bursting. 913Packet bursting is a transmission technique whereby the wireless 914medium is acquired once to send multiple frames and the interframe 915spacing is reduced. 916This technique can significantly increase throughput by reducing 917transmission overhead. 918Packet bursting is supported by the 802.11e QoS specification 919and some devices that do not support QoS may still be capable. 920By default packet bursting is enabled if a device is capable 921of doing it. 922To disable packet bursting, use 923.Fl burst . 924.It Cm chanlist Ar channels 925Set the desired channels to use when scanning for access 926points, neighbors in an IBSS network, or looking for unoccupied 927channels when operating as an access point. 928The set of channels is specified as a comma-separated list with 929each element in the list representing either a single channel number or a range 930of the form 931.Dq Li a-b . 932Channel numbers must be in the range 1 to 255 and be permissible 933according to the operating characteristics of the device. 934.It Cm channel Ar number 935Set a single desired channel. 936Channels range from 1 to 255, but the exact selection available 937depends on the region your adaptor was manufactured for. 938Setting 939the channel to 940.Li any , 941or 942.Cm - 943will clear any desired channel and, if the device is marked up, 944force a scan for a channel to operate on. 945Alternatively the frequency, in megahertz, may be specified 946instead of the channel number. 947.Pp 948When there are several ways to use a channel the channel 949number/frequency may be appended with attributes to clarify. 950For example, if a device is capable of operating on channel 6 951with 802.11n and 802.11g then one can specify that g-only use 952should be used by specifying ``6:g''. 953Similarly the channel width can be specified by appending it 954with ``/''; e.g. ``6/40'' specifies a 40MHz wide channel, 955These attributes can be combined as in: ``6:ht/40''. 956The full set of flags specified following a `:'' are: 957.Cm a 958(802.11a), 959.Cm b 960(802.11b), 961.Cm d 962(Atheros Dynamic Turbo mode), 963.Cm g 964(802.11g), 965.Cm h 966or 967.Cm n 968(802.11n aka HT), 969.Cm s 970(Atheros Static Turbo mode), 971and 972.Cm t 973(Atheros Dynamic Turbo mode, or appended to ``st'' and ``dt''). 974The full set of channel widths following a '/' are: 975.Cm 5 976(5MHz aka quarter-rate channel), 977.Cm 10 978(10MHz aka half-rate channel), 979.Cm 20 980(20MHz mostly for use in specifying ht20), 981and 982.Cm 40 983(40MHz mostly for use in specifying ht40), 984In addition, 985a 40MHz HT channel specification may include the location 986of the extension channel by appending ``+'' or ``-'' for above and below, 987respectively; e.g. ``2437:ht/40+'' specifies 40MHz wide HT operation 988with the center channel at frequency 2437 and the extension channel above. 989.It Cm country Ar name 990Set the country code to use in calculating the regulatory constraints 991for operation. 992In particular the set of available channels, how the wireless device 993will operation on the channels, and the maximum transmit power that 994can be used on a channel are defined by this setting. 995Country/Region codes are specified as a 2-character abbreviation 996defined by ISO 3166 or using a longer, but possibly ambiguous, spelling; 997e.g. "ES" and "Spain". 998The set of country codes are taken from /etc/regdomain.xml and can also 999be viewed with the ``list countries'' request. 1000Note that not all devices support changing the country code from a default 1001setting; typically stored in EEPROM. 1002See also 1003.Cm regdomain , 1004.Cm indoor , 1005.Cm outdoor , 1006and 1007.Cm anywhere . 1008.It Cm dfs 1009Enable Dynamic Frequency Selection (DFS) as specified in 802.11h. 1010DFS embodies several facilities including detection of overlapping 1011radar signals, dynamic transmit power control, and channel selection 1012according to a least-congested criteria. 1013DFS support is mandatory for some 5Ghz frequencies in certain 1014locales (e.g. ETSI). 1015By default DFS is enabled according to the regulatory definitions 1016specified in /etc/regdomain.xml and the current country code, regdomain, 1017and channel. 1018Note the underlying device (and driver) must support radar detection 1019for full DFS support to work. 1020To be fully compliant with the local regulatory agency frequencies that 1021require DFS should not be used unless it is fully supported. 1022Use 1023.Fl dfs 1024to disable this functionality for testing. 1025.It Cm dotd 1026Enable support for the 802.11d specification (default). 1027When this support is enabled in station mode, beacon frames that advertise 1028a country code different than the currently configured country code will 1029cause an event to be dispatched to user applications. 1030This event can be used by the station to adopt that country code and 1031operate according to the associated regulatory constraints. 1032When operating as an access point with 802.11d enabled the beacon and 1033probe response frames transmitted will advertise the current regulatory 1034domain settings. 1035To disable 802.11d use 1036.Fl dotd . 1037.It Cm doth 1038Enable 802.11h support including spectrum management. 1039When 802.11h is enabled beacon and probe response frames will have 1040the SpectrumMgt bit set in the capabilities field and 1041country and power constraint information elements will be present. 1042802.11h support also includes handling Channel Switch Announcements (CSA) 1043which are a mechanism to coordinate channel changes by an access point. 1044By default 802.11h is enabled if the device is capable. 1045To disable 802.11h use 1046.Fl doth . 1047.It Cm deftxkey Ar index 1048Set the default key to use for transmission. 1049Typically this is only set when using WEP encryption. 1050Note that you must set a default transmit key 1051for the system to know which key to use in encrypting outbound traffic. 1052The 1053.Cm weptxkey 1054is an alias for this request; it is provided for backwards compatibility. 1055.It Cm dtimperiod Ar period 1056Set the 1057DTIM 1058period for transmitting buffered multicast data frames when 1059operating in ap mode. 1060The 1061.Ar period 1062specifies the number of beacon intervals between DTIM 1063and must be in the range 1 to 15. 1064By default DTIM is 1 (i.e., DTIM occurs at each beacon). 1065.It Cm dturbo 1066Enable the use of Atheros Dynamic Turbo mode when communicating with 1067another Dynamic Turbo-capable station. 1068Dynamic Turbo mode is an Atheros-specific mechanism by which 1069stations switch between normal 802.11 operation and a ``boosted'' 1070mode in which a 40MHz wide channel is used for communication. 1071Stations using Dynamic Turbo mode operate boosted only when the 1072channel is free of non-dturbo stations; when a non-dturbo station 1073is identified on the channel all stations will automatically drop 1074back to normal operation. 1075By default, Dynamic Turbo mode is not enabled, even if the device is capable. 1076Note that turbo mode (dynamic or static) is only allowed on some 1077channels depending on the regulatory constraints; use the 1078.Cm list chan 1079command to identify the channels where turbo mode may be used. 1080To disable Dynamic Turbo mode use 1081.Fl dturbo . 1082.It Cm dwds 1083Enable Dynamic WDS (DWDS) support. 1084DWDS is a facility by which 4-address traffic can be carried between 1085stations operating in infrastructure mode. 1086A station first associates to an access point and authenticates using 1087normal procedures (e.g. WPA). 1088Then 4-address frames are passed to carry traffic for stations 1089operating on either side of the wireless link. 1090DWDS extends the normal WDS mechanism by leveraging existing security 1091protocols and eliminating static binding. 1092.Pp 1093When DWDS is enabled on an access point 4-address frames received from 1094an authorized station will generate a ``DWDS discovery'' event to user 1095applications. 1096This event should be used to create a WDS interface that is bound 1097to the remote station (and usually plumbed into a bridge). 1098Once the WDS interface is up and running 4-address traffic then logically 1099flows through that interface. 1100.Pp 1101When DWDS is enabled on a station, traffic with a destination address 1102different from the peer station are encapsulated in a 4-address frame 1103and transmitted to the peer. 1104All 4-address traffic uses the security information of the stations 1105(e.g. cryptographic keys). 1106A station is associated using 802.11n facilities may transport 11074-address traffic using these same mechanisms; this depends on available 1108resources and capabilities of the device. 1109The DWDS implementation guards against layer 2 routing loops of 1110multicast traffic. 1111.It Cm ff 1112Enable the use of Atheros Fast Frames when communicating with 1113another Fast Frames-capable station. 1114Fast Frames are an encapsulation technique by which two 802.3 1115frames are transmitted in a single 802.11 frame. 1116This can noticeably improve throughput but requires that the 1117receiving station understand how to decapsulate the frame. 1118Fast frame use is negotiated using the Atheros 802.11 vendor-specific 1119protocol extension so enabling use is safe when communicating with 1120non-Atheros devices. 1121By default, use of fast frames is enabled if the device is capable. 1122To explicitly disable fast frames, use 1123.Fl ff . 1124.It Cm fragthreshold Ar length 1125Set the threshold for which transmitted frames are broken into fragments. 1126The 1127.Ar length 1128argument is the frame size in bytes and must be in the range 256 to 2346. 1129Setting 1130.Ar length 1131to 1132.Li 2346 , 1133.Cm any , 1134or 1135.Cm - 1136disables transmit fragmentation. 1137Not all adapters honor the fragmentation threshold. 1138.It Cm hidessid 1139When operating as an access point, do not broadcast the SSID 1140in beacon frames or respond to probe request frames unless 1141they are directed to the ap (i.e., they include the ap's SSID). 1142By default, the SSID is included in beacon frames and 1143undirected probe request frames are answered. 1144To re-enable the broadcast of the SSID etc., use 1145.Fl hidessid . 1146.It Cm ht 1147Enable use of High Throughput (HT) when using 802.11n (default). 1148The 802.11n specification includes mechanisms for operation 1149on 20MHz and 40MHz wide channels using different signalling mechanisms 1150than specified in 802.11b, 802.11g, and 802.11a. 1151Stations negotiate use of these facilities, termed HT20 and HT40, 1152when they associate. 1153To disable all use of 802.11n use 1154.Fl ht . 1155To disable use of HT20 (e.g. to force only HT40 use) use 1156.Fl ht20 . 1157To disable use of HT40 use 1158.Fl ht40 . 1159.Pp 1160HT configuration is used to ``auto promote'' operation 1161when several choices are available. 1162For example, if a station associates to an 11n-capable access point 1163it controls whether the station uses legacy operation, HT20, or HT40. 1164When an 11n-capable device is setup as an access point and 1165Auto Channel Selection is used to locate a channel to operate on, 1166HT configuration controls whether legacy, HT20, or HT40 operation is setup 1167on the selected channel. 1168If a fixed channel is specified for a station then HT configuration can 1169be given as part of the channel specification; e.g. 6:ht/20 to setup 1170HT20 operation on channel 6. 1171.It Cm htcompat 1172Enable use of compatibility support for pre-802.11n devices (default). 1173The 802.11n protocol specification went through several incompatible iterations. 1174Some vendors implemented 11n support to older specifications that 1175will not interoperate with a purely 11n-compliant station. 1176In particular the information elements included in management frames 1177for old devices are different. 1178When compatibility support is enabled both standard and compatible data 1179will be provided. 1180Stations that associate using the compatibility mechanisms are flagged 1181in ``list sta''. 1182To disable compatibility support use 1183.Fl htcompat . 1184.It Cm htprotmode Ar technique 1185For interfaces operating in 802.11n, use the specified 1186.Ar technique 1187for protecting HT frames in a mixed legacy/HT network. 1188The set of valid techniques is 1189.Cm off , 1190and 1191.Cm rts 1192(RTS/CTS, default). 1193Technique names are case insensitive. 1194.It Cm inact 1195Enable inactivity processing for stations associated to an 1196access point (default). 1197When operating as an access point the 802.11 layer monitors 1198the activity of each associated station. 1199When a station is inactive for 5 minutes it will send several 1200``probe frames'' to see if the station is still present. 1201If no response is received then the station is deauthenticated. 1202Applications that prefer to handle this work can disable this 1203facility by using 1204.Fl inact . 1205.It Cm indoor 1206Set the location to use in calculating regulatory constraints. 1207The location is also advertised in beacon and probe response frames 1208when 802.11d is enabled with 1209.Cm dotd . 1210See also 1211.Cm outdoor , 1212.Cm anywhere , 1213.Cm country , 1214and 1215.Cm regdomain . 1216.It Cm list active 1217Display the list of channels available for use taking into account 1218any restrictions set with the 1219.Cm chanlist 1220directive. 1221See the description of 1222.Cm list chan 1223for more information. 1224.It Cm list caps 1225Display the adaptor's capabilities, including the operating 1226modes supported. 1227.It Cm list chan 1228Display the list of channels available for use. 1229Channels are shown with their IEEE channel number, equivalent 1230frequency, and usage modes. 1231Channels identified as 1232.Ql 11g 1233are also usable in 1234.Ql 11b 1235mode. 1236Channels identified as 1237.Ql 11a Turbo 1238may be used only for Atheros' Static Turbo mode 1239(specified with 1240.Cm mediaopt turbo ) . 1241Channels marked with a 1242.Ql * 1243have a regulatory constraint that they be passively scanned. 1244This means a station is not permitted to transmit on the channel until 1245it identifies the channel is being used for 802.11 communication; 1246typically by hearing a beacon frame from an access point operating 1247on the channel. 1248.Cm list freq 1249is another way of requesting this information. 1250By default a compacted list of channels is displayed; if the 1251.Fl v 1252option is specified then all channels are shown. 1253.It Cm list countries 1254Display the set of country codes and regulatory domains that can be 1255used in regulatory configuration. 1256.It Cm list mac 1257Display the current MAC Access Control List state. 1258Each address is prefixed with a character that indicates the 1259current policy applied to it: 1260.Ql + 1261indicates the address is allowed access, 1262.Ql - 1263indicates the address is denied access, 1264.Ql * 1265indicates the address is present but the current policy open 1266(so the ACL is not consulted). 1267.It Cm list mesh 1268Displays the mesh routing table, used for forwarding packets on a mesh 1269network. 1270.It Cm list regdomain 1271Display the current regulatory settings including the available channels 1272and transmit power caps. 1273.It Cm list roam 1274Display the parameters that govern roaming operation. 1275.It Cm list txparam 1276Display the parameters that govern transmit operation. 1277.It Cm list txpower 1278Display the transmit power caps for each channel. 1279.It Cm list scan 1280Display the access points and/or ad-hoc neighbors 1281located in the vicinity. 1282This information may be updated automatically by the adapter 1283with a 1284.Cm scan 1285request or through background scanning. 1286Depending on the capabilities of the stations the following 1287flags can be included in the output: 1288.Bl -tag -width 3n 1289.It Li A 1290Authorized. 1291Indicates that the station is permitted to send/receive data frames. 1292.It Li E 1293Extended Rate Phy (ERP). 1294Indicates that the station is operating in an 802.11g network 1295using extended transmit rates. 1296.It Li H 1297High Throughput (HT). 1298Indicates that the station is using HT transmit rates. 1299If a `+' follows immediately after then the station associated 1300using deprecated mechanisms supported only when 1301.Cm htcompat 1302is enabled. 1303.It Li P 1304Power Save. 1305Indicates that the station is operating in power save mode. 1306.It Li Q 1307Quality of Service (QoS). 1308Indicates that the station is using QoS encapsulation for 1309data frame. 1310QoS encapsulation is enabled only when WME mode is enabled. 1311.It Li T 1312Transitional Security Network (TSN). 1313Indicates that the station associated using TSN; see also 1314.Cm tsn 1315below. 1316.It Li W 1317Wi-Fi Protected Setup (WPS). 1318Indicates that the station associated using WPS. 1319.El 1320.Pp 1321By default interesting information elements captured from the neighboring 1322stations are displayed at the end of each row. 1323Possible elements include: 1324.Cm WME 1325(station supports WME), 1326.Cm WPA 1327(station supports WPA), 1328.Cm WPS 1329(station supports WPS), 1330.Cm RSN 1331(station supports 802.11i/RSN), 1332.Cm HTCAP 1333(station supports 802.11n/HT communication), 1334.Cm ATH 1335(station supports Atheros protocol extensions), 1336.Cm VEN 1337(station supports unknown vendor-specific extensions). 1338If the 1339.Fl v 1340flag is used all the information elements and their 1341contents will be shown. 1342Specifying the 1343.Fl v 1344flag also enables display of long SSIDs. 1345The 1346.Cm list ap 1347command is another way of requesting this information. 1348.It Cm list sta 1349When operating as an access point display the stations that are 1350currently associated. 1351When operating in ad-hoc mode display stations identified as 1352neighbors in the IBSS. 1353When operating in mesh mode display stations identified as 1354neighbors in the MBSS. 1355When operating in station mode display the access point. 1356Capabilities advertised by the stations are described under 1357the 1358.Cm scan 1359request. 1360Depending on the capabilities of the stations the following 1361flags can be included in the output: 1362.Bl -tag -width 3n 1363.It Li A 1364Authorized. 1365Indicates that the station is permitted to send/receive data frames. 1366.It Li E 1367Extended Rate Phy (ERP). 1368Indicates that the station is operating in an 802.11g network 1369using extended transmit rates. 1370.It Li H 1371High Throughput (HT). 1372Indicates that the station is using HT transmit rates. 1373If a `+' follows immediately after then the station associated 1374using deprecated mechanisms supported only when 1375.Cm htcompat 1376is enabled. 1377.It Li P 1378Power Save. 1379Indicates that the station is operating in power save mode. 1380.It Li Q 1381Quality of Service (QoS). 1382Indicates that the station is using QoS encapsulation for 1383data frame. 1384QoS encapsulation is enabled only when WME mode is enabled. 1385.It Li T 1386Transitional Security Network (TSN). 1387Indicates that the station associated using TSN; see also 1388.Cm tsn 1389below. 1390.It Li W 1391Wi-Fi Protected Setup (WPS). 1392Indicates that the station associated using WPS. 1393.El 1394.Pp 1395By default information elements received from associated stations 1396are displayed in a short form; the 1397.Fl v 1398flag causes this information to be displayed symbolically. 1399.It Cm list wme 1400Display the current channel parameters to use when operating in WME mode. 1401If the 1402.Fl v 1403option is specified then both channel and BSS parameters are displayed 1404for each AC (first channel, then BSS). 1405When WME mode is enabled for an adaptor this information will be 1406displayed with the regular status; this command is mostly useful 1407for examining parameters when WME mode is disabled. 1408See the description of the 1409.Cm wme 1410directive for information on the various parameters. 1411.It Cm lscan 1412A variant of 1413.Cm scan 1414(see below) that displays long SSIDs. 1415.It Cm maxretry Ar count 1416Set the maximum number of tries to use in sending unicast frames. 1417The default setting is 6 but drivers may override this with a value 1418they choose. 1419.It Cm mcastrate Ar rate 1420Set the rate for transmitting multicast/broadcast frames. 1421Rates are specified as megabits/second in decimal; e.g.\& 5.5 for 5.5 Mb/s. 1422This rate should be valid for the current operating conditions; 1423if an invalid rate is specified drivers are free to choose an 1424appropriate rate. 1425.It Cm mgtrate Ar rate 1426Set the rate for transmitting management and/or control frames. 1427Rates are specified as megabits/second in decimal; e.g.\& 5.5 for 5.5 Mb/s. 1428.It Cm outdoor 1429Set the location to use in calculating regulatory constraints. 1430The location is also advertised in beacon and probe response frames 1431when 802.11d is enabled with 1432.Cm dotd . 1433See also 1434.Cm anywhere , 1435.Cm country , 1436.Cm indoor , 1437and 1438.Cm regdomain . 1439.It Cm powersave 1440Enable powersave operation. 1441When operating as a client, the station will conserve power by 1442periodically turning off the radio and listening for 1443messages from the access point telling it there are packets waiting. 1444The station must then retrieve the packets. 1445Not all devices support power save operation as a client. 1446The 802.11 specification requires that all access points support 1447power save but some drivers do not. 1448Use 1449.Fl powersave 1450to disable powersave operation when operating as a client. 1451.It Cm powersavemode Ar mode 1452Set powersave mode. 1453The set of valid modes is 1454.Cm off 1455(same as 1456.Fl powersave ) , 1457.Cm on 1458(same as 1459.Cm powersave ) , 1460and 1461.Cm cam 1462(same as 1463.Cm powersave ) . 1464.It Cm powersavesleep Ar sleep 1465Set the desired max powersave sleep time in TU's (1024 usecs). 1466By default the max powersave sleep time is 100 TU's. 1467.It Cm protmode Ar technique 1468For interfaces operating in 802.11g, use the specified 1469.Ar technique 1470for protecting OFDM frames in a mixed 11b/11g network. 1471The set of valid techniques is 1472.Cm off , cts 1473(CTS to self), 1474and 1475.Cm rtscts 1476(RTS/CTS). 1477Technique names are case insensitive. 1478Not all devices support 1479.Cm cts 1480as a protection technique. 1481.It Cm pureg 1482When operating as an access point in 802.11g mode allow only 148311g-capable stations to associate (11b-only stations are not 1484permitted to associate). 1485To allow both 11g and 11b-only stations to associate, use 1486.Fl pureg . 1487.It Cm puren 1488When operating as an access point in 802.11n mode allow only 1489HT-capable stations to associate (legacy stations are not 1490permitted to associate). 1491To allow both HT and legacy stations to associate, use 1492.Fl puren . 1493.It Cm regdomain Ar sku 1494Set the regulatory domain to use in calculating the regulatory constraints 1495for operation. 1496In particular the set of available channels, how the wireless device 1497will operation on the channels, and the maximum transmit power that 1498can be used on a channel are defined by this setting. 1499Regdomain codes (SKU's) are taken from /etc/regdomain.xml and can also 1500be viewed with the ``list countries'' request. 1501Note that not all devices support changing the regdomain from a default 1502setting; typically stored in EEPROM. 1503See also 1504.Cm country , 1505.Cm indoor , 1506.Cm outdoor , 1507and 1508.Cm anywhere . 1509.It Cm rifs 1510Enable use of Reduced InterFrame Spacing (RIFS) when operating in 802.11n 1511on an HT channel. 1512Note that RIFS must be supported by both the station and access point 1513for it to be used. 1514To disable RIFS use 1515.Fl rifs . 1516.It Cm roam:rate Ar rate 1517Set the threshold for controlling roaming when operating in a BSS. 1518The 1519.Ar rate 1520parameter specifies the transmit rate in megabits 1521at which roaming should be considered. 1522If the current transmit rate drops below this setting and background scanning 1523is enabled, then the system will check if a more desirable access point is 1524available and switch over to it. 1525The current scan cache contents are used if they are considered 1526valid according to the 1527.Cm scanvalid 1528parameter; otherwise a background scan operation is triggered before 1529any selection occurs. 1530Each channel type has a separate rate threshold; the default values are: 153112 Mb/s (11a), 2 Mb/s (11b), 2 Mb/s (11g), MCS 1 (11na, 11ng). 1532.It Cm roam:rssi Ar rssi 1533Set the threshold for controlling roaming when operating in a BSS. 1534The 1535.Ar rssi 1536parameter specifies the receive signal strength in dBm units 1537at which roaming should be considered. 1538If the current rssi drops below this setting and background scanning 1539is enabled, then the system will check if a more desirable access point is 1540available and switch over to it. 1541The current scan cache contents are used if they are considered 1542valid according to the 1543.Cm scanvalid 1544parameter; otherwise a background scan operation is triggered before 1545any selection occurs. 1546Each channel type has a separate rssi threshold; the default values are 1547all 7 dBm. 1548.It Cm roaming Ar mode 1549When operating as a station, control how the system will 1550behave when communication with the current access point 1551is broken. 1552The 1553.Ar mode 1554argument may be one of 1555.Cm device 1556(leave it to the hardware device to decide), 1557.Cm auto 1558(handle either in the device or the operating system\[em]as appropriate), 1559.Cm manual 1560(do nothing until explicitly instructed). 1561By default, the device is left to handle this if it is 1562capable; otherwise, the operating system will automatically 1563attempt to reestablish communication. 1564Manual mode is used by applications such as 1565.Xr wpa_supplicant 8 1566that want to control the selection of an access point. 1567.It Cm rtsthreshold Ar length 1568Set the threshold for which 1569transmitted frames are preceded by transmission of an 1570RTS 1571control frame. 1572The 1573.Ar length 1574argument 1575is the frame size in bytes and must be in the range 1 to 2346. 1576Setting 1577.Ar length 1578to 1579.Li 2346 , 1580.Cm any , 1581or 1582.Cm - 1583disables transmission of RTS frames. 1584Not all adapters support setting the RTS threshold. 1585.It Cm scan 1586Initiate a scan of neighboring stations, wait for it to complete, and 1587display all stations found. 1588Only the super-user can initiate a scan. 1589See 1590.Cm list scan 1591for information on the display. 1592By default a background scan is done; otherwise a foreground 1593scan is done and the station may roam to a different access point. 1594The 1595.Cm list scan 1596request can be used to show recent scan results without 1597initiating a new scan. 1598.It Cm scanvalid Ar threshold 1599Set the maximum time the scan cache contents are considered valid; 1600i.e. will be used without first triggering a scan operation to 1601refresh the data. 1602The 1603.Ar threshold 1604parameter is specified in seconds and defaults to 60 seconds. 1605The minimum setting for 1606.Ar threshold 1607is 10 seconds. 1608One should take care setting this threshold; if it is set too low 1609then attempts to roam to another access point may trigger unnecessary 1610background scan operations. 1611.It Cm shortgi 1612Enable use of Short Guard Interval when operating in 802.11n 1613on an HT channel. 1614NB: this currently enables Short GI on both HT40 and HT20 channels. 1615To disable Short GI use 1616.Fl shortgi . 1617.It Cm smps 1618Enable use of Static Spatial Multiplexing Power Save (SMPS) 1619when operating in 802.11n. 1620A station operating with Static SMPS maintains only a single 1621receive chain active (this can significantly reduce power consumption). 1622To disable SMPS use 1623.Fl smps . 1624.It Cm smpsdyn 1625Enable use of Dynamic Spatial Multiplexing Power Save (SMPS) 1626when operating in 802.11n. 1627A station operating with Dynamic SMPS maintains only a single 1628receive chain active but switches to multiple receive chains when it 1629receives an RTS frame (this can significantly reduce power consumption). 1630Note that stations cannot distinguish between RTS/CTS intended to 1631enable multiple receive chains and those used for other purposes. 1632To disable SMPS use 1633.Fl smps . 1634.It Cm ssid Ar ssid 1635Set the desired Service Set Identifier (aka network name). 1636The SSID is a string up to 32 characters 1637in length and may be specified as either a normal string or in 1638hexadecimal when preceded by 1639.Ql 0x . 1640Additionally, the SSID may be cleared by setting it to 1641.Ql - . 1642.It Cm tdmaslot Ar slot 1643When operating with TDMA, use the specified 1644.Ar slot 1645configuration. 1646The 1647.Ar slot 1648is a number between 0 and the maximum number of slots in the BSS. 1649Note that a station configured as slot 0 is a master and 1650will broadcast beacon frames advertising the BSS; 1651stations configured to use other slots will always 1652scan to locate a master before they ever transmit. 1653By default 1654.Cm tdmaslot 1655is set to 1. 1656.It Cm tdmaslotcnt Ar cnt 1657When operating with TDMA, setup a BSS with 1658.Ar cnt 1659slots. 1660The slot count may be at most 8. 1661The current implementation is only tested with two stations 1662(i.e. point to point applications). 1663This setting is only meaningful when a station is configured as slot 0; 1664other stations adopt this setting from the BSS they join. 1665By default 1666.Cm tdmaslotcnt 1667is set to 2. 1668.It Cm tdmaslotlen Ar len 1669When operating with TDMA, setup a BSS such that each station has a slot 1670.Ar len 1671microseconds long. 1672The slot length must be at least 150 microseconds (1/8 TU) 1673and no more than 65 milliseconds. 1674Note that setting too small a slot length may result in poor channel 1675bandwidth utilization due to factors such as timer granularity and 1676guard time. 1677This setting is only meaningful when a station is configured as slot 0; 1678other stations adopt this setting from the BSS they join. 1679By default 1680.Cm tdmaslotlen 1681is set to 10 milliseconds. 1682.It Cm tdmabintval Ar intval 1683When operating with TDMA, setup a BSS such that beacons are transmitted every 1684.Ar intval 1685superframes to synchronize the TDMA slot timing. 1686A superframe is defined as the number of slots times the slot length; e.g. 1687a BSS with two slots of 10 milliseconds has a 20 millisecond superframe. 1688The beacon interval may not be zero. 1689A lower setting of 1690.Cm tdmabintval 1691causes the timers to be resynchronized more often; this can be help if 1692significant timer drift is observed. 1693By default 1694.Cm tdmabintval 1695is set to 5. 1696.It Cm tsn 1697When operating as an access point with WPA/802.11i allow legacy 1698stations to associate using static key WEP and open authentication. 1699To disallow legacy station use of WEP, use 1700.Fl tsn . 1701.It Cm txpower Ar power 1702Set the power used to transmit frames. 1703The 1704.Ar power 1705argument is specified in .5 dBm units. 1706Out of range values are truncated. 1707Typically only a few discreet power settings are available and 1708the driver will use the setting closest to the specified value. 1709Not all adapters support changing the transmit power. 1710.It Cm ucastrate Ar rate 1711Set a fixed rate for transmitting unicast frames. 1712Rates are specified as megabits/second in decimal; e.g.\& 5.5 for 5.5 Mb/s. 1713This rate should be valid for the current operating conditions; 1714if an invalid rate is specified drivers are free to choose an 1715appropriate rate. 1716.It Cm wepmode Ar mode 1717Set the desired WEP mode. 1718Not all adapters support all modes. 1719The set of valid modes is 1720.Cm off , on , 1721and 1722.Cm mixed . 1723The 1724.Cm mixed 1725mode explicitly tells the adaptor to allow association with access 1726points which allow both encrypted and unencrypted traffic. 1727On these adapters, 1728.Cm on 1729means that the access point must only allow encrypted connections. 1730On other adapters, 1731.Cm on 1732is generally another name for 1733.Cm mixed . 1734Modes are case insensitive. 1735.It Cm weptxkey Ar index 1736Set the WEP key to be used for transmission. 1737This is the same as setting the default transmission key with 1738.Cm deftxkey . 1739.It Cm wepkey Ar key Ns | Ns Ar index : Ns Ar key 1740Set the selected WEP key. 1741If an 1742.Ar index 1743is not given, key 1 is set. 1744A WEP key will be either 5 or 13 1745characters (40 or 104 bits) depending on the local network and the 1746capabilities of the adaptor. 1747It may be specified either as a plain 1748string or as a string of hexadecimal digits preceded by 1749.Ql 0x . 1750For maximum portability, hex keys are recommended; 1751the mapping of text keys to WEP encryption is usually driver-specific. 1752In particular, the 1753.Tn Windows 1754drivers do this mapping differently to 1755.Fx . 1756A key may be cleared by setting it to 1757.Ql - . 1758If WEP is supported then there are at least four keys. 1759Some adapters support more than four keys. 1760If that is the case, then the first four keys 1761(1-4) will be the standard temporary keys and any others will be adaptor 1762specific keys such as permanent keys stored in NVRAM. 1763.Pp 1764Note that you must set a default transmit key with 1765.Cm deftxkey 1766for the system to know which key to use in encrypting outbound traffic. 1767.It Cm wme 1768Enable Wireless Multimedia Extensions (WME) support, if available, 1769for the specified interface. 1770WME is a subset of the IEEE 802.11e standard to support the 1771efficient communication of realtime and multimedia data. 1772To disable WME support, use 1773.Fl wme . 1774Another name for this parameter is 1775.Cm wmm . 1776.Pp 1777The following parameters are meaningful only when WME support is in use. 1778Parameters are specified per-AC (Access Category) and 1779split into those that are used by a station when acting 1780as an access point and those for client stations in the BSS. 1781The latter are received from the access point and may not be changed 1782(at the station). 1783The following Access Categories are recognized: 1784.Pp 1785.Bl -tag -width ".Cm AC_BK" -compact 1786.It Cm AC_BE 1787(or 1788.Cm BE ) 1789best effort delivery, 1790.It Cm AC_BK 1791(or 1792.Cm BK ) 1793background traffic, 1794.It Cm AC_VI 1795(or 1796.Cm VI ) 1797video traffic, 1798.It Cm AC_VO 1799(or 1800.Cm VO ) 1801voice traffic. 1802.El 1803.Pp 1804AC parameters are case-insensitive. 1805Traffic classification is done in the operating system using the 1806vlan priority associated with data frames or the 1807ToS (Type of Service) indication in IP-encapsulated frames. 1808If neither information is present, traffic is assigned to the 1809Best Effort (BE) category. 1810.Bl -tag -width indent 1811.It Cm ack Ar ac 1812Set the ACK policy for QoS transmissions by the local station; 1813this controls whether or not data frames transmitted by a station 1814require an ACK response from the receiving station. 1815To disable waiting for an ACK use 1816.Fl ack . 1817This parameter is applied only to the local station. 1818.It Cm acm Ar ac 1819Enable the Admission Control Mandatory (ACM) mechanism 1820for transmissions by the local station. 1821To disable the ACM use 1822.Fl acm . 1823On stations in a BSS this parameter is read-only and indicates 1824the setting received from the access point. 1825NB: ACM is not supported right now. 1826.It Cm aifs Ar ac Ar count 1827Set the Arbitration Inter Frame Spacing (AIFS) 1828channel access parameter to use for transmissions 1829by the local station. 1830On stations in a BSS this parameter is read-only and indicates 1831the setting received from the access point. 1832.It Cm cwmin Ar ac Ar count 1833Set the CWmin channel access parameter to use for transmissions 1834by the local station. 1835On stations in a BSS this parameter is read-only and indicates 1836the setting received from the access point. 1837.It Cm cwmax Ar ac Ar count 1838Set the CWmax channel access parameter to use for transmissions 1839by the local station. 1840On stations in a BSS this parameter is read-only and indicates 1841the setting received from the access point. 1842.It Cm txoplimit Ar ac Ar limit 1843Set the Transmission Opportunity Limit channel access parameter 1844to use for transmissions by the local station. 1845This parameter defines an interval of time when a WME station 1846has the right to initiate transmissions onto the wireless medium. 1847On stations in a BSS this parameter is read-only and indicates 1848the setting received from the access point. 1849.It Cm bss:aifs Ar ac Ar count 1850Set the AIFS channel access parameter to send to stations in a BSS. 1851This parameter is meaningful only when operating in ap mode. 1852.It Cm bss:cwmin Ar ac Ar count 1853Set the CWmin channel access parameter to send to stations in a BSS. 1854This parameter is meaningful only when operating in ap mode. 1855.It Cm bss:cwmax Ar ac Ar count 1856Set the CWmax channel access parameter to send to stations in a BSS. 1857This parameter is meaningful only when operating in ap mode. 1858.It Cm bss:txoplimit Ar ac Ar limit 1859Set the TxOpLimit channel access parameter to send to stations in a BSS. 1860This parameter is meaningful only when operating in ap mode. 1861.El 1862.It Cm wps 1863Enable Wireless Privacy Subscriber support. 1864Note that WPS support requires a WPS-capable supplicant. 1865To disable this function use 1866.Fl wps . 1867.El 1868.Pp 1869The following parameters support an optional access control list 1870feature available with some adapters when operating in ap mode; see 1871.Xr wlan_acl 4 . 1872This facility allows an access point to accept/deny association 1873requests based on the MAC address of the station. 1874Note that this feature does not significantly enhance security 1875as MAC address spoofing is easy to do. 1876.Bl -tag -width indent 1877.It Cm mac:add Ar address 1878Add the specified MAC address to the database. 1879Depending on the policy setting association requests from the 1880specified station will be allowed or denied. 1881.It Cm mac:allow 1882Set the ACL policy to permit association only by 1883stations registered in the database. 1884.It Cm mac:del Ar address 1885Delete the specified MAC address from the database. 1886.It Cm mac:deny 1887Set the ACL policy to deny association only by 1888stations registered in the database. 1889.It Cm mac:kick Ar address 1890Force the specified station to be deauthenticated. 1891This typically is done to block a station after updating the 1892address database. 1893.It Cm mac:open 1894Set the ACL policy to allow all stations to associate. 1895.It Cm mac:flush 1896Delete all entries in the database. 1897.It Cm mac:radius 1898Set the ACL policy to permit association only by 1899stations approved by a RADIUS server. 1900Note that this feature requires the 1901.Xr hostapd 8 1902program be configured to do the right thing 1903as it handles the RADIUS processing 1904(and marks stations as authorized). 1905.El 1906.Pp 1907The following parameters are related to a wireless interface operating in mesh 1908mode: 1909.Bl -tag -width indent 1910.It Cm meshid Ar meshid 1911Set the desired Mesh Identifier. 1912The Mesh ID is a string up to 32 characters in length. 1913A mesh interface must have a Mesh Identifier specified 1914to reach an operational state. 1915.It Cm meshttl Ar ttl 1916Set the desired ``time to live'' for mesh forwarded packets; 1917this is the number of hops a packet may be forwarded before 1918it is discarded. 1919The default setting for 1920.Cm meshttl 1921is 31. 1922.It Cm meshpeering 1923Enable or disable peering with neighbor mesh stations. 1924Stations must peer before any data packets can be exchanged. 1925By default 1926.Cm meshpeering 1927is enabled. 1928.It Cm meshforward 1929Enable or disable forwarding packets by a mesh interface. 1930By default 1931.Cm meshforward 1932is enabled. 1933.It Cm meshmetric Ar protocol 1934Set the specified 1935.Ar protocol 1936as the link metric protocol used on a mesh network. 1937The default protocol is called 1938.Ar AIRTIME . 1939The mesh interface will restart after changing this setting. 1940.It Cm meshpath Ar protocol 1941Set the specified 1942.Ar protocol 1943as the path selection protocol used on a mesh network. 1944The only available protocol at the moment is called 1945.Ar HWMP 1946(Hybrid Wireless Mesh Protocol). 1947The mesh interface will restart after changing this setting. 1948.It Cm hwmprootmode Ar mode 1949Stations on a mesh network can operate as ``root nodes.'' 1950Root nodes try to find paths to all mesh nodes and advertise themselves 1951regularly. 1952When there is a root mesh node on a network, other mesh nodes can setup 1953paths between themselves faster because they can use the root node 1954to find the destination. 1955This path may not be the best, but on-demand 1956routing will eventually find the best path. 1957The following modes are recognized: 1958.Pp 1959.Bl -tag -width ".Cm PROACTIVE" -compact 1960.It Cm DISABLED 1961Disable root mode. 1962.It Cm NORMAL 1963Send broadcast path requests every two seconds. 1964Nodes on the mesh without a path to this root mesh station with try to 1965discover a path to us. 1966.It Cm PROACTIVE 1967Send broadcast path requests every two seconds and every node must reply 1968with a path reply even if it already has a path to this root mesh station, 1969.It Cm RANN 1970Send broadcast root announcement (RANN) frames. 1971Nodes on the mesh without a path to this root mesh station with try to 1972discover a path to us. 1973.El 1974By default 1975.Cm hwmprootmode 1976is set to 1977.Ar DISABLED . 1978.It Cm hwmpmaxhops Ar cnt 1979Set the maximum number of hops allowed in an HMWP path to 1980.Ar cnt . 1981The default setting for 1982.Cm hwmpmaxhops 1983is 31. 1984.El 1985.Pp 1986The following parameters are for compatibility with other systems: 1987.Bl -tag -width indent 1988.It Cm nwid Ar ssid 1989Another name for the 1990.Cm ssid 1991parameter. 1992Included for 1993.Nx 1994compatibility. 1995.It Cm stationname Ar name 1996Set the name of this station. 1997The station name is not part of the IEEE 802.11 1998protocol though some interfaces support it. 1999As such it only 2000seems to be meaningful to identical or virtually identical equipment. 2001Setting the station name is identical in syntax to setting the SSID. 2002One can also use 2003.Cm station 2004for 2005.Bsx 2006compatibility. 2007.It Cm wep 2008Another way of saying 2009.Cm wepmode on . 2010Included for 2011.Bsx 2012compatibility. 2013.It Fl wep 2014Another way of saying 2015.Cm wepmode off . 2016Included for 2017.Bsx 2018compatibility. 2019.It Cm nwkey key 2020Another way of saying: 2021.Dq Li "wepmode on weptxkey 1 wepkey 1:key wepkey 2:- wepkey 3:- wepkey 4:-" . 2022Included for 2023.Nx 2024compatibility. 2025.It Cm nwkey Xo 2026.Sm off 2027.Ar n : k1 , k2 , k3 , k4 2028.Sm on 2029.Xc 2030Another way of saying 2031.Dq Li "wepmode on weptxkey n wepkey 1:k1 wepkey 2:k2 wepkey 3:k3 wepkey 4:k4" . 2032Included for 2033.Nx 2034compatibility. 2035.It Fl nwkey 2036Another way of saying 2037.Cm wepmode off . 2038Included for 2039.Nx 2040compatibility. 2041.El 2042.Pp 2043The following parameters are specific to bridge interfaces: 2044.Bl -tag -width indent 2045.It Cm addm Ar interface 2046Add the interface named by 2047.Ar interface 2048as a member of the bridge. 2049The interface is put into promiscuous mode 2050so that it can receive every packet sent on the network. 2051.It Cm deletem Ar interface 2052Remove the interface named by 2053.Ar interface 2054from the bridge. 2055Promiscuous mode is disabled on the interface when 2056it is removed from the bridge. 2057.It Cm maxaddr Ar size 2058Set the size of the bridge address cache to 2059.Ar size . 2060The default is 100 entries. 2061.It Cm timeout Ar seconds 2062Set the timeout of address cache entries to 2063.Ar seconds 2064seconds. 2065If 2066.Ar seconds 2067is zero, then address cache entries will not be expired. 2068The default is 1200 seconds. 2069.It Cm addr 2070Display the addresses that have been learned by the bridge. 2071.It Cm static Ar interface-name Ar address 2072Add a static entry into the address cache pointing to 2073.Ar interface-name . 2074Static entries are never aged out of the cache or re-placed, even if the 2075address is seen on a different interface. 2076.It Cm deladdr Ar address 2077Delete 2078.Ar address 2079from the address cache. 2080.It Cm flush 2081Delete all dynamically-learned addresses from the address cache. 2082.It Cm flushall 2083Delete all addresses, including static addresses, from the address cache. 2084.It Cm discover Ar interface 2085Mark an interface as a 2086.Dq discovering 2087interface. 2088When the bridge has no address cache entry 2089(either dynamic or static) 2090for the destination address of a packet, 2091the bridge will forward the packet to all 2092member interfaces marked as 2093.Dq discovering . 2094This is the default for all interfaces added to a bridge. 2095.It Fl discover Ar interface 2096Clear the 2097.Dq discovering 2098attribute on a member interface. 2099For packets without the 2100.Dq discovering 2101attribute, the only packets forwarded on the interface are broadcast 2102or multicast packets and packets for which the destination address 2103is known to be on the interface's segment. 2104.It Cm learn Ar interface 2105Mark an interface as a 2106.Dq learning 2107interface. 2108When a packet arrives on such an interface, the source 2109address of the packet is entered into the address cache as being a 2110destination address on the interface's segment. 2111This is the default for all interfaces added to a bridge. 2112.It Fl learn Ar interface 2113Clear the 2114.Dq learning 2115attribute on a member interface. 2116.It Cm span Ar interface 2117Add the interface named by 2118.Ar interface 2119as a span port on the bridge. 2120Span ports transmit a copy of every frame received by the bridge. 2121This is most useful for snooping a bridged network passively on 2122another host connected to one of the span ports of the bridge. 2123.It Fl span Ar interface 2124Delete the interface named by 2125.Ar interface 2126from the list of span ports of the bridge. 2127.It Cm stp Ar interface 2128Enable Spanning Tree protocol on 2129.Ar interface . 2130The 2131.Xr bridge 4 2132driver has support for the IEEE 802.1D Spanning Tree protocol (STP). 2133Spanning Tree is used to detect and remove loops in a network topology. 2134.It Fl stp Ar interface 2135Disable Spanning Tree protocol on 2136.Ar interface . 2137This is the default for all interfaces added to a bridge. 2138.It Cm maxage Ar seconds 2139Set the time that a Spanning Tree protocol configuration is valid. 2140The default is 20 seconds. 2141The minimum is 1 second and the maximum is 255 seconds. 2142.It Cm fwddelay Ar seconds 2143Set the time that must pass before an interface begins forwarding 2144packets when Spanning Tree is enabled. 2145The default is 15 seconds. 2146The minimum is 1 second and the maximum is 255 seconds. 2147.It Cm hellotime Ar seconds 2148Set the time between broadcasting of Spanning Tree protocol 2149configuration messages. 2150The default is 2 seconds. 2151The minimum is 1 second and the maximum is 255 seconds. 2152.It Cm priority Ar value 2153Set the bridge priority for Spanning Tree. 2154The default is 32768. 2155The minimum is 0 and the maximum is 65536. 2156.It Cm ifpriority Ar interface Ar value 2157Set the Spanning Tree priority of 2158.Ar interface 2159to 2160.Ar value . 2161The default is 128. 2162The minimum is 0 and the maximum is 255. 2163.Pp 2164The priority is used to select which interface out of all 2165forwarding and bonded interfaces with the same MAC 2166to output a packet on whe 2167.Cm link2 2168mode is not being used. 2169Note that interfaces in the 'blocking' state do not participate 2170in the priority selection. 2171If the priorities are the same on a non-bonded member, the 2172designated member will be used. 2173.It Cm ifpathcost Ar interface Ar value 2174Set the Spanning Tree path cost of 2175.Ar interface 2176to 2177.Ar value . 2178The default is 55. 2179The minimum is 0 and the maximum is 65535. 2180.Pp 2181The path cost is added to both incoming and outgoing packets on the 2182member, lower values will make the member more valuable. 2183.It Cm ifbondweight Ar interface Ar value 2184Set the number of packets to output on a bonded member before 2185round-robining to the next member. 2186The default is 1. 2187Larger values or different values for each member can be used 2188if bursting would be beneficial or if the outgoing bandwidth 2189on each of the members is asymmetric. 2190For example, one specify a value of 6 on tap0 and 4 on tap1 2191for a 6:4 ratio. 2192Remember that this also controls packet bursting. 2193.It Cm link0 2194The link0 option enables transparent bridging mode. 2195The bridge will make every effort to retain the Ethernet header 2196when forwarding packets between interfaces, making the bridging 2197function work more like a hardware bridge device. 2198.It Cm link1 2199The link1 option enables keepalive transmission and automatically 2200places a member into a special blocked mode if no keepalive reception 2201occurs. 2202If either sides of the link uses this option then both sides must use 2203this option. 2204This option is impemented by sending CFG updates on the hello interval 2205to the remote. 2206The link is considered lost after 10 intervals (typically 20 seconds). 2207.It Cm link2 2208The link2 option enables channel bonding (see also ifbondweight). 2209All member interfaces with the same mac address are considered to 2210be in a bonding group. 2211When something like 2212.Xr tap 4 2213is used, you can manually control or copy the mac to create bonding groups. 2214When interface bonding is enabled normally blocked interfaces belonging 2215to the same bonding group as an active forwarding interface will be 2216changed to the bonding state. 2217Both sides of link the member represents must operate in bonding mode 2218for this to work, otherwise the remote end may decide to throw away 2219half your packets. 2220.El 2221.Pp 2222The following parameters are specific to IP tunnel interfaces, 2223.Xr gif 4 : 2224.Bl -tag -width indent 2225.It Cm tunnel Ar src_addr dest_addr 2226Configure the physical source and destination address for IP tunnel 2227interfaces. 2228The arguments 2229.Ar src_addr 2230and 2231.Ar dest_addr 2232are interpreted as the outer source/destination for the encapsulating 2233IPv4/IPv6 header. 2234.It Fl tunnel 2235Unconfigure the physical source and destination address for IP tunnel 2236interfaces previously configured with 2237.Cm tunnel . 2238.It Cm deletetunnel 2239Another name for the 2240.Fl tunnel 2241parameter. 2242.El 2243.Pp 2244The following parameters are specific to 2245.Xr vlan 4 2246interfaces: 2247.Bl -tag -width indent 2248.It Cm vlan Ar vlan_tag 2249Set the VLAN tag value to 2250.Ar vlan_tag . 2251This value is a 16-bit number which is used to create an 802.1Q 2252VLAN header for packets sent from the 2253.Xr vlan 4 2254interface. 2255Note that 2256.Cm vlan 2257and 2258.Cm vlandev 2259must both be set at the same time. 2260.It Cm vlandev Ar iface 2261Associate the physical interface 2262.Ar iface 2263with a 2264.Xr vlan 4 2265interface. 2266Packets transmitted through the 2267.Xr vlan 4 2268interface will be 2269diverted to the specified physical interface 2270.Ar iface 2271with 802.1Q VLAN encapsulation. 2272Packets with 802.1Q encapsulation received 2273by the parent interface with the correct VLAN tag will be diverted to 2274the associated 2275.Xr vlan 4 2276pseudo-interface. 2277The 2278.Xr vlan 4 2279interface is assigned a 2280copy of the parent interface's flags and the parent's Ethernet address. 2281The 2282.Cm vlandev 2283and 2284.Cm vlan 2285must both be set at the same time. 2286If the 2287.Xr vlan 4 2288interface already has 2289a physical interface associated with it, this command will fail. 2290To 2291change the association to another physical interface, the existing 2292association must be cleared first. 2293.Pp 2294Note: if the hardware tagging capability 2295is set on the parent interface, the 2296.Xr vlan 4 2297pseudo 2298interface's behavior changes: 2299the 2300.Xr vlan 4 2301interface recognizes that the 2302parent interface supports insertion and extraction of VLAN tags on its 2303own (usually in firmware) and that it should pass packets to and from 2304the parent unaltered. 2305.It Fl vlandev Op Ar iface 2306If the driver is a 2307.Xr vlan 4 2308pseudo device, disassociate the parent interface from it. 2309This breaks the link between the 2310.Xr vlan 4 2311interface and its parent, 2312clears its VLAN tag, flags and its link address and shuts the interface down. 2313The 2314.Ar iface 2315argument is useless and hence deprecated. 2316.El 2317.Pp 2318The following parameters are specific to 2319.Xr carp 4 2320interfaces: 2321.Bl -tag -width indent 2322.It Cm advbase Ar seconds 2323Specifies the base of the advertisement interval in seconds. 2324The acceptable values are 1 to 255. 2325The default value is 1. 2326.\" The default value is 2327.\" .Dv CARP_DFLTINTV . 2328.It Cm advskew Ar interval 2329Specifies the skew to add to the base advertisement interval to 2330make one host advertise slower than another host. 2331It is specified in 1/256 of seconds. 2332The acceptable values are 1 to 254. 2333The default value is 0. 2334.It Cm pass Ar phrase 2335Set the authentication key to 2336.Ar phrase . 2337.It Cm vhid Ar n 2338Set the virtual host ID. 2339This is a required setting. 2340Acceptable values are 1 to 255. 2341.El 2342.Pp 2343The 2344.Nm 2345utility displays the current configuration for a network interface 2346when no optional parameters are supplied. 2347If a protocol family is specified, 2348.Nm 2349will report only the details specific to that protocol family. 2350.Pp 2351If the 2352.Fl m 2353flag is passed before an interface name, 2354.Nm 2355will display the capability list, 2356the maximum amount of data 2357that TCP segmentation offloading is allowed to aggregate and 2358all of the supported media for the specified interface. 2359If 2360.Fl L 2361flag is supplied, address lifetime is displayed for IPv6 addresses, 2362as time offset string. 2363.Pp 2364Optionally, the 2365.Fl a 2366flag may be used instead of an interface name. 2367This flag instructs 2368.Nm 2369to display information about all interfaces in the system. 2370The 2371.Fl d 2372flag limits this to interfaces that are down, 2373.Fl u 2374limits this to interfaces that are up, 2375.Fl g 2376limits this to members of the specified group of interfaces, and 2377.Fl G 2378excludes members of the specified group from the list. 2379Both 2380.Fl g 2381and 2382.Fl G 2383flags may be specified to apply both conditions. 2384Only one 2385.Fl g 2386flag should be specified, as the later one overrides previous ones 2387(same for the 2388.Fl G 2389flag). 2390The argument of 2391.Fl g 2392or 2393.Fl G 2394flag may contain shell patterns but should be quoted in that case. 2395When no arguments are given, 2396.Fl a 2397is implied. 2398.Pp 2399The 2400.Fl l 2401flag may be used to list all available interfaces on the system, with 2402no other additional information. 2403Use of this flag is mutually exclusive 2404with all other flags and commands, except for 2405.Fl d 2406(only list interfaces that are down) 2407and 2408.Fl u 2409(only list interfaces that are up). 2410.Pp 2411The 2412.Fl v 2413flag may be used to get more verbose status for an interface. 2414.Pp 2415The 2416.Fl C 2417flag may be used to list all of the interface cloners available on 2418the system, with no additional information. 2419Use of this flag is mutually exclusive with all other flags and commands. 2420.Pp 2421The 2422.Fl k 2423flag causes keying information for the interface, if available, to be 2424printed. 2425For example, the values of 802.11 WEP keys will be printed, if accessible to 2426the current user. 2427This information is not printed by default, as it may be considered 2428sensitive. 2429.Pp 2430If the network interface driver is not present in the kernel then 2431.Nm 2432will attempt to load it. 2433The 2434.Fl n 2435flag disables this behavior. 2436.Pp 2437Only the super-user may modify the configuration of a network interface. 2438.Sh DIAGNOSTICS 2439Messages indicating the specified interface does not exist, the 2440requested address is unknown, or the user is not privileged and 2441tried to alter an interface's configuration. 2442.Sh SEE ALSO 2443.Xr netstat 1 , 2444.Xr carp 4 , 2445.Xr ifmedia 4 , 2446.Xr netintro 4 , 2447.Xr polling 4 , 2448.Xr vlan 4 , 2449.\" .Xr eon 5 , 2450.Xr rc 8 , 2451.Xr routed 8 , 2452.Xr sysctl 8 2453.Sh HISTORY 2454The 2455.Nm 2456utility appeared in 2457.Bx 4.2 . 2458.Sh BUGS 2459Basic IPv6 node operation requires a link-local address on each 2460interface configured for IPv6. 2461Normally, such an address is automatically configured by the 2462kernel on each interface added to the system; this behaviour may 2463be disabled by setting the sysctl MIB variable 2464.Va net.inet6.ip6.auto_linklocal 2465to 0. 2466.Pp 2467If you delete such an address using 2468.Nm , 2469the kernel may act very odd. 2470Do this at your own risk. 2471