1.\" $NetBSD: ifconfig.8,v 1.92 2007/12/16 13:49:22 degroote Exp $ 2.\" 3.\" Copyright (c) 1983, 1991, 1993 4.\" The Regents of the University of California. All rights reserved. 5.\" 6.\" Redistribution and use in source and binary forms, with or without 7.\" modification, are permitted provided that the following conditions 8.\" are met: 9.\" 1. Redistributions of source code must retain the above copyright 10.\" notice, this list of conditions and the following disclaimer. 11.\" 2. Redistributions in binary form must reproduce the above copyright 12.\" notice, this list of conditions and the following disclaimer in the 13.\" documentation and/or other materials provided with the distribution. 14.\" 3. Neither the name of the University nor the names of its contributors 15.\" may be used to endorse or promote products derived from this software 16.\" without specific prior written permission. 17.\" 18.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 19.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 20.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 21.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 22.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 23.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 24.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 25.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 26.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 27.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 28.\" SUCH DAMAGE. 29.\" 30.\" @(#)ifconfig.8 8.4 (Berkeley) 6/1/94 31.\" 32.Dd January 9, 2007 33.Dt IFCONFIG 8 34.Os 35.Sh NAME 36.Nm ifconfig 37.Nd configure network interface parameters 38.Sh SYNOPSIS 39.Nm 40.Ar interface address_family 41.Oo 42.Ar address 43.Op Ar dest_address 44.Oc 45.Op Ar parameters 46.Nm 47.Op Fl hLmvz 48.Ar interface 49.Op Ar protocol_family 50.Nm 51.Fl a 52.Op Fl bdhLmsuvz 53.Op Ar protocol_family 54.Nm 55.Fl l 56.Op Fl bdsu 57.Nm 58.Fl s 59.Ar interface 60.Nm 61.Fl C 62.Sh DESCRIPTION 63.Nm 64is used to assign an address 65to a network interface and/or configure 66network interface parameters. 67.Nm 68must be used at boot time to define the network address 69of each interface present on a machine; it may also be used at 70a later time to redefine an interface's address 71or other operating parameters. 72.Pp 73Available operands for 74.Nm : 75.Bl -tag -width Ds 76.It Ar address 77For the 78.Tn DARPA-Internet 79family, 80the address is either a host name present in the host name data 81base, 82.Xr hosts 5 , 83or a 84.Tn DARPA 85Internet address expressed in the Internet standard 86.Dq dot notation . 87For the Xerox Network Systems(tm) family, 88addresses are 89.Ar net:a.b.c.d.e.f , 90where 91.Ar net 92is the assigned network number 93.Pq in decimal , 94and each of the six bytes of the host number, 95.Ar a 96through 97.Ar f , 98are specified in hexadecimal. 99The host number may be omitted on Ethernet interfaces, 100which use the hardware physical address, 101and on interfaces other than the first. 102For the 103.Tn ISO 104family, addresses are specified as a long hexadecimal string, 105as in the Xerox family. 106However, two consecutive dots imply a zero 107byte, and the dots are optional, if the user wishes to 108.Pq carefully 109count out long strings of digits in network byte order. 110.It Ar address_family 111Specifies the 112.Ar address_family 113which affects interpretation of the remaining parameters. 114Since an interface can receive transmissions in differing protocols 115with different naming schemes, specifying the address family is recommended. 116The address or protocol families currently 117supported are 118.Dq inet , 119.Dq inet6 , 120.Dq atalk , 121.Dq iso , 122and 123.Dq ns . 124.It Ar interface 125The 126.Ar interface 127parameter is a string of the form 128.Dq name unit , 129for example, 130.Dq en0 131.El 132.Pp 133The following parameters may be set with 134.Nm : 135.Bl -tag -width dest_addressxx 136.It Cm advbase Ar n 137If the driver is a 138.Xr carp 4 139pseudo-device, set the base advertisement interval to 140.Ar n 141seconds. 142This ia an 8-bit number; the default value is 1 second. 143.It Cm advskew Ar n 144If the driver is a 145.Xr carp 4 146pseudo-device, skew the advertisement interval by 147.Ar n . 148This is an 8-bit number; the default value is 0. 149.Pp 150Taken together the 151.Cm advbase 152indicate how frequently, in seconds, the host will advertise the fact that it 153considers itself the master of the virtual host. 154The formula is 155.Cm advbase 156+ 157.Pf ( Cm advskew 158/ 256). 159If the master does not advertise within three times this interval, this host 160will begin advertising as master. 161.It Cm alias 162Establish an additional network address for this interface. 163This is sometimes useful when changing network numbers, and 164one wishes to accept packets addressed to the old interface. 165.It Fl alias 166Remove the specified network address alias. 167.It Cm arp 168Enable the use of the Address Resolution Protocol in mapping 169between network level addresses and link level addresses 170.Pq default . 171This is currently implemented for mapping between 172.Tn DARPA 173Internet 174addresses and Ethernet addresses. 175.It Fl arp 176Disable the use of the Address Resolution Protocol. 177.It Cm anycast 178.Pq inet6 only 179Set the IPv6 anycast address bit. 180.It Fl anycast 181.Pq inet6 only 182Clear the IPv6 anycast address bit. 183.It Cm broadcast Ar mask 184.Pq Inet only 185Specify the address to use to represent broadcasts to the 186network. 187The default broadcast address is the address with a host part of all 1's. 188.It Cm carpdev Ar iface 189If the driver is a 190.Xr carp 4 191pseudo-device, attach it to 192.Ar iface . 193If not specified, the kernel will attempt to select an interface with 194a subnet matching that of the carp interface. 195.It Cm debug 196Enable driver dependent debugging code; usually, this turns on 197extra console error logging. 198.It Fl debug 199Disable driver dependent debugging code. 200.ne 1i 201.It Cm delete 202Remove the network address specified. 203This would be used if you incorrectly specified an alias, or it 204was no longer needed. 205If you have incorrectly set an NS address having the side effect 206of specifying the host portion, removing all NS addresses will 207allow you to respecify the host portion. 208.Cm delete 209does not work for IPv6 addresses. 210Use 211.Fl alias 212with explicit IPv6 address instead. 213.It Ar dest_address 214Specify the address of the correspondent on the other end 215of a point to point link. 216.It Cm down 217Mark an interface ``down''. 218When an interface is 219marked ``down'', the system will not attempt to 220transmit messages through that interface. 221If possible, the interface will be reset to disable reception as well. 222This action does not automatically disable routes using the interface. 223.It Cm ipdst 224This is used to specify an Internet host who is willing to receive 225ip packets encapsulating NS packets bound for a remote network. 226An apparent point to point link is constructed, and 227the address specified will be taken as the NS address and network 228of the destination. 229IP encapsulation of 230.Tn CLNP 231packets is done differently. 232.It Cm media Ar type 233Set the media type of the interface to 234.Ar type . 235Some interfaces support the mutually exclusive use of one of several 236different physical media connectors. 237For example, a 10Mb/s Ethernet 238interface might support the use of either 239.Tn AUI 240or twisted pair connectors. 241Setting the media type to 242.Dq 10base5 243or 244.Dq AUI 245would change the currently active connector to the AUI port. 246Setting it to 247.Dq 10baseT 248or 249.Dq UTP 250would activate twisted pair. 251Refer to the interfaces' driver 252specific man page for a complete list of the available types. 253.It Cm mediaopt Ar opts 254Set the specified media options on the interface. 255.Ar opts 256is a comma delimited list of options to apply to the interface. 257Refer to the interfaces' driver specific man page for a complete 258list of available options. 259.It Fl mediaopt Ar opts 260Disable the specified media options on the interface. 261.It Cm mode Ar mode 262If the driver supports the media selection system, set the specified 263operating mode on the interface to 264.Ar mode . 265For IEEE 802.11 wireless interfaces that support multiple operating modes 266this directive is used to select between 802.11a 267.Pq Dq 11a , 268802.11b 269.Pq Dq 11b , 270and 802.11g 271.Pq Dq 11g 272operating modes. 273.It Cm instance Ar minst 274Set the media instance to 275.Ar minst . 276This is useful for devices which have multiple physical layer interfaces 277.Pq PHYs . 278Setting the instance on such devices may not be strictly required 279by the network interface driver as the driver may take care of this 280automatically; see the driver's manual page for more information. 281.It Cm metric Ar n 282Set the routing metric of the interface to 283.Ar n , 284default 0. 285The routing metric is used by the routing protocol 286.Pq Xr routed 8 . 287Higher metrics have the effect of making a route 288less favorable; metrics are counted as addition hops 289to the destination network or host. 290.It Cm mtu Ar n 291Set the maximum transmission unit of the interface to 292.Ar n . 293Most interfaces don't support this option. 294.It Cm netmask Ar mask 295.Pq inet, inet6, and ISO 296Specify how much of the address to reserve for subdividing 297networks into sub-networks. 298The mask includes the network part of the local address 299and the subnet part, which is taken from the host field of the address. 300The mask can be specified as a single hexadecimal number 301with a leading 0x, with a dot-notation Internet address, 302or with a pseudo-network name listed in the network table 303.Xr networks 5 . 304The mask contains 1's for the bit positions in the 32-bit address 305which are to be used for the network and subnet parts, 306and 0's for the host part. 307The mask should contain at least the standard network portion, 308and the subnet field should be contiguous with the network 309portion. 310.Pp 311For INET and INET6 addresses, the netmask can also be given with 312slash-notation after the address 313.Pq e.g 192.168.17.3/24 . 314.\" see 315.\" Xr eon 5 . 316.It Cm nsellength Ar n 317.Pf ( Tn ISO 318only) 319This specifies a trailing number of bytes for a received 320.Tn NSAP 321used for local identification, the remaining leading part of which is 322taken to be the 323.Tn NET 324.Pq Network Entity Title . 325The default value is 1, which is conformant to US 326.Tn GOSIP . 327When an ISO address is set in an ifconfig command, 328it is really the 329.Tn NSAP 330which is being specified. 331For example, in 332.Tn US GOSIP , 33320 hex digits should be 334specified in the 335.Tn ISO NSAP 336to be assigned to the interface. 337There is some evidence that a number different from 1 may be useful 338for 339.Tn AFI 34037 type addresses. 341.It Cm state Ar state 342Explicitly force the 343.Xr carp 4 344pseudo-device to enter this state. 345Valid states are 346.Ar init , 347.Ar backup , 348and 349.Ar master . 350.It Cm frag Ar threshold 351.Pq IEEE 802.11 devices only 352Configure the fragmentation threshold for IEEE 802.11-based wireless 353network interfaces. 354.It Cm ssid Ar id 355.Pq IEEE 802.11 devices only 356Configure the Service Set Identifier (a.k.a. the network name) 357for IEEE 802.11-based wireless network interfaces. 358The 359.Ar id 360can either be any text string up to 32 characters in length, 361or a series of up to 64 hexadecimal digits preceded by 362.Dq 0x . 363Setting 364.Ar id 365to the empty string allows the interface to connect to any available 366access point. 367.It Cm nwid Ar id 368Synonym for 369.Dq ssid . 370.It Cm hidessid 371.Pq IEEE 802.11 devices only 372When operating as an access point, do not broadcast the SSID 373in beacon frames or respond to probe request frames unless 374they are directed to the ap (i.e., they include the ap's SSID). 375By default, the SSID is included in beacon frames and 376undirected probe request frames are answered. 377.It Fl hidessid 378.Pq IEEE 802.11 devices only 379When operating as an access point, broadcast the SSID 380in beacon frames and answer and respond to undirected probe 381request frames (default). 382.It Cm nwkey Ar key 383.Pq IEEE 802.11 devices only 384Enable WEP encryption for IEEE 802.11-based wireless network interfaces 385with the 386.Ar key . 387The 388.Ar key 389can either be a string, a series of hexadecimal digits preceded by 390.Dq 0x , 391or a set of keys in the form 392.Ar n:k1,k2,k3,k4 , 393where 394.Ar n 395specifies which of keys will be used for all transmitted packets, 396and four keys, 397.Ar k1 398through 399.Ar k4 , 400are configured as WEP keys. 401Note that the order must be match within same network if multiple keys 402are used. 403For IEEE 802.11 wireless network, the length of each key is restricted to 40440 bits, i.e. 5-character string or 10 hexadecimal digits, 405while the WaveLAN/IEEE Gold cards accept the 104 bits 406.Pq 13 characters 407key. 408.It Cm nwkey Cm persist 409.Pq IEEE 802.11 devices only 410Enable WEP encryption for IEEE 802.11-based wireless network interfaces 411with the persistent key written in the network card. 412.It Cm nwkey Cm persist: Ns Ar key 413.Pq IEEE 802.11 devices only 414Write the 415.Ar key 416to the persistent memory of the network card, and 417enable WEP encryption for IEEE 802.11-based wireless network interfaces 418with the 419.Ar key . 420.It Fl nwkey 421.Pq IEEE 802.11 devices only 422Disable WEP encryption for IEEE 802.11-based wireless network interfaces. 423.It Cm apbridge 424.Pq IEEE 802.11 devices only 425When operating as an access point, pass packets between 426wireless clients directly (default). 427.It Fl apbridge 428.Pq IEEE 802.11 devices only 429When operating as an access point, pass packets through 430the system so that they can be forwared using some other mechanism. 431Disabling the internal bridging is useful when traffic 432is to be processed with packet filtering. 433.It Cm pass Ar passphrase 434If the driver is a 435.Xr carp 4 436pseudo-device, set the authentication key to 437.Ar passphrase . 438There is no passphrase by default 439.It Cm powersave 440.Pq IEEE 802.11 devices only 441Enable 802.11 power saving mode. 442.It Fl powersave 443.Pq IEEE 802.11 devices only 444Disable 802.11 power saving mode. 445.It Cm powersavesleep Ar duration 446.Pq IEEE 802.11 devices only 447Set the receiver sleep duration in milliseconds for 802.11 power saving mode. 448.It Cm bssid Ar bssid 449.Pq IEEE 802.11 devices only 450Set the desired BSSID for IEEE 802.11-based wireless network interfaces. 451.It Fl bssid 452.Pq IEEE 802.11 devices only 453Unset the desired BSSID for IEEE 802.11-based wireless network interfaces. 454The interface will automatically select a BSSID in this mode, which is 455the default. 456.It Cm chan Ar chan 457.Pq IEEE 802.11 devices only 458Select the channel 459.Pq radio frequency 460to be used for IEEE 802.11-based wireless network interfaces. 461.It Fl chan 462.Pq IEEE 802.11 devices only 463Unset the desired channel to be used 464for IEEE 802.11-based wireless network interfaces. 465It doesn't affect the channel to be created for IBSS or hostap mode. 466.It Bk -words 467.It Cm list scan 468.Pq IEEE 802.11 devices only 469Display the access points and/or ad-hoc neighbors 470located in the vicinity. 471The 472.Fl v 473flag may be used to display long SSIDs. 474.Fl v 475also causes received information elements to be displayed symbolicaly. 476Only the super-user can use this command. 477.It Cm tunnel Ar src_addr Ns Op Ar ,src_port 478.Ar dest_addr Ns Op Ar ,dest_port 479.Ek 480.Pq IP tunnel devices only 481Configure the physical source and destination address for IP tunnel 482interfaces, including 483.Xr gif 4 . 484The arguments 485.Ar src_addr 486and 487.Ar dest_addr 488are interpreted as the outer source/destination for the encapsulating 489IPv4/IPv6 header. 490.Pp 491On a 492.Xr gre 4 493interface in UDP mode, the arguments 494.Ar src_port 495and 496.Ar dest_port 497are interpreted as the outer source/destination port for the encapsulating 498UDP header. 499.It Cm deletetunnel 500Unconfigure the physical source and destination address for IP tunnel 501interfaces previously configured with 502.Cm tunnel . 503.It Cm create 504Create the specified network pseudo-device. 505.It Cm destroy 506Destroy the specified network pseudo-device. 507.It Cm pltime Ar n 508.Pq inet6 only 509Set preferred lifetime for the address. 510.It Cm prefixlen Ar n 511.Pq inet and inet6 only 512Effect is similar to 513.Cm netmask . 514but you can specify by prefix length by digits. 515.It Cm deprecated 516.Pq inet6 only 517Set the IPv6 deprecated address bit. 518.It Fl deprecated 519.Pq inet6 only 520Clear the IPv6 deprecated address bit. 521.It Cm tentative 522.Pq inet6 only 523Set the IPv6 tentative address bit. 524.It Fl tentative 525.Pq inet6 only 526Clear the IPv6 tentative address bit. 527.It Cm eui64 528.Pq inet6 only 529Fill interface index 530.Pq lowermost 64bit of an IPv6 address 531automatically. 532.It Cm link[0-2] 533Enable special processing of the link level of the interface. 534These three options are interface specific in actual effect, however, 535they are in general used to select special modes of operation. 536An example 537of this is to enable SLIP compression, or to select the connector type 538for some ethernet cards. 539Refer to the man page for the specific driver 540for more information. 541.It Fl link[0-2] 542Disable special processing at the link level with the specified interface. 543.It Cm up 544Mark an interface ``up''. 545This may be used to enable an interface after an ``ifconfig down.'' 546It happens automatically when setting the first address on an interface. 547If the interface was reset when previously marked down, 548the hardware will be re-initialized. 549.It Cm vhid Ar n 550If the driver is a 551.Xr carp 4 552pseudo-device, set the virtual host ID to 553.Ar n . 554Acceptable values are 1 to 255. 555.It Cm vlan Ar vid 556If the interface is a 557.Xr vlan 4 558pseudo-interface, set the VLAN identifier to 559.Ar vid . 560These are the first 12 bits (0-4095) from a 16-bit integer used 561to create an 802.1Q VLAN header for packets sent from the 562.Xr vlan 4 563interface. 564Note that 565.Cm vlan 566and 567.Cm vlanif 568must be set at the same time. 569.It Cm vlanif Ar iface 570If the interface is a 571.Xr vlan 4 572pseudo-interface, associate the physical interface 573.Ar iface 574with it. 575Packets transmitted through the 576.Xr vlan 4 577interface will be diverted to the specified physical interface 578.Ar iface 579with 802.1Q VLAN encapsulation. 580Packets with 802.1Q encapsulation received 581by the physical interface with the correct VLAN tag will be diverted to the 582associated 583.Xr vlan 4 584pseudo-interface. 585The VLAN interface is assigned a copy of the physical 586interface's flags and 587.Tn Ethernet 588address. 589If the 590.Xr vlan 4 591interface already has a physical interface associated with it, this command 592will fail. 593To change the association to another physical interface, the 594existing association must be cleared first. 595Note that 596.Cm vlanif 597and 598.Cm vlan 599must be set at the same time. 600.It Cm agrport Ar iface 601Add 602.Ar iface 603to the 604.Xr agr 4 605interface. 606.It Cm -agrport Ar iface 607Remove 608.Ar iface 609from the 610.Xr agr 4 611interface. 612.It Cm vltime Ar n 613.Pq inet6 only 614Set valid lifetime for the address. 615.It Cm ip4csum 616Shorthand of 617.Dq ip4csum-tx ip4csum-rx 618.It Cm -ip4csum 619Shorthand of 620.Dq -ip4csum-tx -ip4csum-rx 621.It Cm tcp4csum 622Shorthand of 623.Dq tcp4csum-tx tcp4csum-rx 624.It Cm -tcp4csum 625Shorthand of 626.Dq -tcp4csum-tx -tcp4csum-rx 627.It Cm udp4csum 628Shorthand of 629.Dq udp4csum-tx udp4csum-rx 630.It Cm -udp4csum 631Shorthand of 632.Dq -udp4csum-tx -udp4csum-rx 633.It Cm tcp6csum 634Shorthand of 635.Dq tcp6csum-tx tcp6csum-rx 636.It Cm -tcp6csum 637Shorthand of 638.Dq -tcp6csum-tx -tcp6csum-rx 639.It Cm udp6csum 640Shorthand of 641.Dq udp6csum-tx udp6csum-rx 642.It Cm -udp6csum 643Shorthand of 644.Dq -udp6csum-tx -udp6csum-rx 645.It Cm ip4csum-tx 646Enable hardware-assisted IPv4 header checksums for the out-bound direction. 647.It Cm -ip4csum-tx 648Disable hardware-assisted IPv4 header checksums for the out-bound direction. 649.It Cm ip4csum-rx 650Enable hardware-assisted IPv4 header checksums for the in-bound direction. 651.It Cm -ip4csum-rx 652Disable hardware-assisted IPv4 header checksums for the in-bound direction. 653.It Cm tcp4csum-tx 654Enable hardware-assisted TCP/IPv4 checksums for the out-bound direction. 655.It Cm -tcp4csum-tx 656Disable hardware-assisted TCP/IPv4 checksums for the out-bound direction. 657.It Cm tcp4csum-rx 658Enable hardware-assisted TCP/IPv4 checksums for the in-bound direction. 659.It Cm -tcp4csum-rx 660Disable hardware-assisted TCP/IPv4 checksums for the in-bound direction. 661.It Cm udp4csum-tx 662Enable hardware-assisted UDP/IPv4 checksums for the out-bound direction. 663.It Cm -udp4csum-tx 664Disable hardware-assisted UDP/IPv4 checksums for the out-bound direction. 665.It Cm udp4csum-rx 666Enable hardware-assisted UDP/IPv4 checksums for the in-bound direction. 667.It Cm -udp4csum-rx 668Disable hardware-assisted UDP/IPv4 checksums for the in-bound direction. 669.It Cm tcp6csum-tx 670Enable hardware-assisted TCP/IPv6 checksums for the out-bound direction. 671.It Cm -tcp6csum-tx 672Disable hardware-assisted TCP/IPv6 checksums for the out-bound direction. 673.It Cm tcp6csum-rx 674Enable hardware-assisted TCP/IPv6 checksums for the in-bound direction. 675.It Cm -tcp6csum-rx 676Disable hardware-assisted TCP/IPv6 checksums for the in-bound direction. 677.It Cm udp6csum-tx 678Enable hardware-assisted UDP/IPv6 checksums for the out-bound direction. 679.It Cm -udp6csum-tx 680Disable hardware-assisted UDP/IPv6 checksums for the out-bound direction. 681.It Cm udp6csum-rx 682Enable hardware-assisted UDP/IPv6 checksums for the in-bound direction. 683.It Cm -udp6csum-rx 684Disable hardware-assisted UDP/IPv6 checksums for the in-bound direction. 685.It Cm tso4 686Enable hardware-assisted TCP/IPv4 segmentation on interfaces that 687support it. 688.It Cm -tso4 689Disable hardware-assisted TCP/IPv4 segmentation on interfaces that 690support it. 691.It Cm tso6 692Enable hardware-assisted TCP/IPv6 segmentation on interfaces that 693support it. 694.It Cm -tso6 695Disable hardware-assisted TCP/IPv6 segmentation on interfaces that 696support it. 697.El 698.Pp 699.Nm 700displays the current configuration for a network interface 701when no optional parameters are supplied. 702If a protocol family is specified, 703.Nm 704will report only the details specific to that protocol 705family. 706.Pp 707If the 708.Fl s 709flag is passed before an interface name, 710.Nm 711will attempt to query the interface for its media status. 712If the 713interface supports reporting media status, and it reports that it does 714not appear to be connected to a network, 715.Nm 716will exit with status of 1 717.Pq false ; 718otherwise, it will exit with a 719zero 720.Pq true 721exit status. 722Not all interface drivers support media 723status reporting. 724.Pp 725If the 726.Fl m 727flag is passed before an interface name, 728.Nm 729will display all of the supported media for the specified interface. 730If the 731.Fl L 732flag is supplied, address lifetime is displayed for IPv6 addresses, 733as time offset string. 734.Pp 735Optionally, the 736.Fl a 737flag may be used instead of an interface name. 738This flag instructs 739.Nm 740to display information about all interfaces in the system. 741.Fl d 742limits this to interfaces that are down, 743.Fl u 744limits this to interfaces that are up, 745.Fl b 746limits this to broadcast interfaces, and 747.Fl s 748omits interfaces which appear not to be connected to a network. 749.Pp 750The 751.Fl l 752flag may be used to list all available interfaces on the system, with 753no other additional information. 754Use of this flag is mutually exclusive 755with all other flags and commands, except for 756.Fl d 757.Pq only list interfaces that are down , 758.Fl u 759.Pq only list interfaces that are up , 760.Fl s 761.Pq only list interfaces that may be connected , 762.Fl b 763.Pq only list broadcast interfaces . 764.Pp 765The 766.Fl C 767flag may be used to list all of the interface cloners available on 768the system, with no additional information. 769Use of this flag is 770mutually exclusive with all other flags and commands. 771.Pp 772The 773.Fl v 774flag prints statistics on packets sent and received on the given 775interface. 776If 777.Fl h 778is used in conjunction with 779.Fl v , 780the byte statistics will be printed in "human-readable" format. 781The 782.Fl z 783flag is identical to the 784.Fl v 785flag except that it zeros the interface input and output statistics 786after printing them. 787.Pp 788Only the super-user may modify the configuration of a network interface. 789.Sh DIAGNOSTICS 790Messages indicating the specified interface does not exist, the 791requested address is unknown, or the user is not privileged and 792tried to alter an interface's configuration. 793.Sh SEE ALSO 794.Xr netstat 1 , 795.Xr agr 4 , 796.Xr carp 4 , 797.Xr ifmedia 4 , 798.Xr netintro 4 , 799.Xr vlan 4 , 800.Xr ifconfig.if 5 , 801.\" .Xr eon 5 , 802.Xr rc 8 , 803.Xr routed 8 804.Sh HISTORY 805The 806.Nm 807command appeared in 808.Bx 4.2 . 809