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. All advertising materials mentioning features or use of this software 13.\" must display the following acknowledgement: 14.\" This product includes software developed by the University of 15.\" California, Berkeley and its contributors. 16.\" 4. Neither the name of the University nor the names of its contributors 17.\" may be used to endorse or promote products derived from this software 18.\" without specific prior written permission. 19.\" 20.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 21.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 22.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 23.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 24.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 25.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30.\" SUCH DAMAGE. 31.\" 32.\" From: @(#)ifconfig.8 8.3 (Berkeley) 1/5/94 33.\" $Id: ifconfig.8,v 1.12 1997/02/22 14:32:32 peter Exp $ 34.\" 35.Dd February 13, 1996 36.Dt IFCONFIG 8 37.Os BSD 4.2 38.Sh NAME 39.Nm ifconfig 40.Nd configure network interface parameters 41.Sh SYNOPSIS 42.Nm ifconfig 43.Ar interface address_family 44.Oo 45.Ar address 46.Op Ar dest_address 47.Oc 48.Op Ar parameters 49.Nm ifconfig 50.Op Fl m 51.Ar interface 52.Op Ar protocol_family 53.Nm ifconfig 54.Fl a 55.Op Fl m 56.Op Fl d 57.Op Fl u 58.Op Ar protocol_family 59.Nm ifconfig 60.Fl l 61.Op Fl d 62.Op Fl u 63.Sh DESCRIPTION 64.Nm 65is used to assign an address 66to a network interface and/or configure 67network interface parameters. 68.Nm 69must be used at boot time to define the network address 70of each interface present on a machine; it may also be used at 71a later time to redefine an interface's address 72or other operating parameters. 73.Pp 74Available operands for 75.Nm ifconfig : 76.Bl -tag -width Ds 77.It Ar Address 78For the 79.Tn DARPA-Internet 80family, 81the address is either a host name present in the host name data 82base, 83.Xr hosts 5 , 84or a 85.Tn DARPA 86Internet address expressed in the Internet standard 87.Dq dot notation . 88.\" For the Xerox Network Systems(tm) family, 89.\" addresses are 90.\" .Ar net:a.b.c.d.e.f , 91.\" where 92.\" .Ar net 93.\" is the assigned network number (in decimal), 94.\" and each of the six bytes of the host number, 95.\" .Ar a 96.\" through 97.\" .Ar f , 98.\" are specified in hexadecimal. 99.\" The host number may be omitted on 10Mb/s Ethernet interfaces, 100.\" which use the hardware physical address, 101.\" and on interfaces other than the first. 102.\" For the 103.\" .Tn ISO 104.\" family, addresses are specified as a long hexadecimal string, 105.\" as in the Xerox family. However, two consecutive dots imply a zero 106.\" byte, and the dots are optional, if the user wishes to (carefully) 107.\" count out long strings of digits in network byte order. 108.It Ar address_family 109Specifies the 110.Ar address family 111which affects interpretation of the remaining parameters. 112Since an interface can receive transmissions in differing protocols 113with different naming schemes, specifying the address family is recommended. 114The address or protocol families currently 115supported are 116.Dq inet , 117.Dq atalk , 118.\" .Dq iso , 119and 120.Dq ipx . 121.\" and 122.\" .Dq ns . 123.It Ar Interface 124The 125.Ar interface 126parameter is a string of the form 127.Dq name unit , 128for example, 129.Dq en0 130.El 131.Pp 132The following parameters may be set with 133.Nm ifconfig : 134.Bl -tag -width dest_addressxx 135.It Cm alias 136Establish an additional network address for this interface. 137This is sometimes useful when changing network numbers, and 138one wishes to accept packets addressed to the old interface. 139.It Cm arp 140Enable the use of the Address Resolution Protocol in mapping 141between network level addresses and link level addresses (default). 142This is currently implemented for mapping between 143.Tn DARPA 144Internet 145addresses and 10Mb/s Ethernet addresses. 146.It Fl arp 147Disable the use of the Address Resolution Protocol. 148.It Cm broadcast 149(Inet only) 150Specify the address to use to represent broadcasts to the 151network. 152The default broadcast address is the address with a host part of all 1's. 153.It Cm debug 154Enable driver dependent debugging code; usually, this turns on 155extra console error logging. 156.It Fl debug 157Disable driver dependent debugging code. 158.It Cm delete 159Remove the network address specified. 160This would be used if you incorrectly specified an alias, or it 161was no longer needed. 162If you have incorrectly set an NS address having the side effect 163of specifying the host portion, removing all NS addresses will 164allow you to respecify the host portion. 165.It Cm dest_address 166Specify the address of the correspondent on the other end 167of a point to point link. 168.It Cm down 169Mark an interface ``down''. When an interface is 170marked ``down'', the system will not attempt to 171transmit messages through that interface. 172If possible, the interface will be reset to disable reception as well. 173This action does not automatically disable routes using the interface. 174.\" .It Cm ipdst 175.\" This is used to specify an Internet host who is willing to receive 176.\" ip packets encapsulating NS packets bound for a remote network. 177.\" An apparent point to point link is constructed, and 178.\" the address specified will be taken as the NS address and network 179.\" of the destination. 180.\" IP encapsulation of 181.\" .Tn CLNP 182.\" packets is done differently. 183.It Cm media Ar type 184Set the media type of the interface to 185.Ar type . 186Some interfaces support the mutually exclusive use of one of several 187different physical media connectors. For example, a 10Mb/s Ethernet 188interface might support the use of either 189.Tn AUI 190or twisted pair connectors. Setting the media type to 191.Dq 10base5/AUI 192would change the currently active connector to the AUI port. 193Setting it to 194.Dq 10baseT/UTP 195would activate twisted pair. Refer to the interfaces' driver 196specific man page for a complete list of the available types. 197.It Cm mediaopt Ar opts 198Set the specified media options on the interface. 199.Ar opts 200is a comma delimited list of options to apply to the interface. 201Refer to the interfaces' driver specific man page for a complete 202list of available options. 203.It Fl mediaopt Ar opts 204Disable the specified media options on the interface. 205.It Cm metric Ar n 206Set the routing metric of the interface to 207.Ar n , 208default 0. 209The routing metric is used by the routing protocol 210.Pq Xr routed 8 . 211Higher metrics have the effect of making a route 212less favorable; metrics are counted as addition hops 213to the destination network or host. 214.It Cm mtu Ar n 215Set the maximum transmission unit of the interface to 216.Ar n , 217default is interface specific. 218The mtu is used to limit the size of packets that are transmitted on an 219interface. 220Not all interfaces support setting the mtu, and some interfaces have 221range restrictions. 222.It Cm netmask Ar mask 223.\" (Inet and ISO) 224(Inet only) 225Specify how much of the address to reserve for subdividing 226networks into sub-networks. 227The mask includes the network part of the local address 228and the subnet part, which is taken from the host field of the address. 229The mask can be specified as a single hexadecimal number 230with a leading 0x, with a dot-notation Internet address, 231or with a pseudo-network name listed in the network table 232.Xr networks 5 . 233The mask contains 1's for the bit positions in the 32-bit address 234which are to be used for the network and subnet parts, 235and 0's for the host part. 236The mask should contain at least the standard network portion, 237and the subnet field should be contiguous with the network 238portion. 239.\" see 240.\" Xr eon 5 . 241.\" .It Cm nsellength Ar n 242.\" .Pf ( Tn ISO 243.\" only) 244.\" This specifies a trailing number of bytes for a received 245.\" .Tn NSAP 246.\" used for local identification, the remaining leading part of which is 247.\" taken to be the 248.\" .Tn NET 249.\" (Network Entity Title). 250.\" The default value is 1, which is conformant to US 251.\" .Tn GOSIP . 252.\" When an ISO address is set in an ifconfig command, 253.\" it is really the 254.\" .Tn NSAP 255.\" which is being specified. 256.\" For example, in 257.\" .Tn US GOSIP , 258.\" 20 hex digits should be 259.\" specified in the 260.\" .Tn ISO NSAP 261.\" to be assigned to the interface. 262.\" There is some evidence that a number different from 1 may be useful 263.\" for 264.\" .Tn AFI 265.\" 37 type addresses. 266.It Cm range 267Under appletalk, set the interface to respond to a 268.Em netrange. 269of the form startnet-endnet. Appletalk uses this scheme instead of 270netmasks though FreeBSD impliments it internally as a set of netmasks. 271.It Cm phase 272The argument following this specifies the version (phase) of the 273Appletalk network attached to the interface. Values of 1 or 2 are permitted. 274.It Cm link[0-2] 275Enable special processing of the link level of the interface. 276These three options are interface specific in actual effect, however, 277they are in general used to select special modes of operation. An example 278of this is to enable SLIP compression, or to select the connector type 279for some ethernet cards. Refer to the man page for the specific driver 280for more information. 281.It Fl link[0-2] 282Disable special processing at the link level with the specified interface. 283.It Cm up 284Mark an interface ``up''. 285This may be used to enable an interface after an ``ifconfig down.'' 286It happens automatically when setting the first address on an interface. 287If the interface was reset when previously marked down, 288the hardware will be re-initialized. 289.El 290.Pp 291.Nm 292displays the current configuration for a network interface 293when no optional parameters are supplied. 294If a protocol family is specified, 295Ifconfig will report only the details specific to that protocol family. 296.Pp 297If the 298.Fl m 299flag is passed before an interface name, 300.Nm 301will display all of the supported media for the specified interface. 302.Pp 303Optionally, the 304.Fl a 305flag may be used instead of an interface name. This flag instructs 306.Nm 307to display information about all interfaces in the system. 308.Fl d 309limits this to interfaces that are down, and 310.Fl u 311limits this to interfaces that are up. 312.Pp 313The 314.Fl l 315flag may be used to list all available interfaces on the system, with 316no other additional information. Use of this flag is mutually exclusive 317with all other flags and commands, except for 318.Fl d 319(only list interfaces that are down) 320and 321.Fl u 322(only list interfaces that are up). 323.Pp 324Only the super-user may modify the configuration of a network interface. 325.Sh DIAGNOSTICS 326Messages indicating the specified interface does not exit, the 327requested address is unknown, or the user is not privileged and 328tried to alter an interface's configuration. 329.Sh SEE ALSO 330.Xr netstat 1 , 331.Xr netintro 4 , 332.Xr rc 8 , 333.Xr routed 8 334.\" .Xr eon 5 335.Sh HISTORY 336The 337.Nm 338command appeared in 339.Bx 4.2 . 340