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 acknowledgment: 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 1.17 1998/06/08 02:00:45 danny 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.Fl a 51.Op Fl d 52.Op Fl u 53.Op Ar address_family 54.Nm ifconfig 55.Fl l 56.Op Fl d 57.Op Fl u 58.Op Ar address_family 59.Sh DESCRIPTION 60.Nm Ifconfig 61is used to assign an address 62to a network interface and/or configure 63network interface parameters. 64.Nm Ifconfig 65must be used at boot time to define the network address 66of each interface present on a machine; it may also be used at 67a later time to redefine an interface's address 68or other operating parameters. 69.Pp 70The following options are available: 71.Bl -tag -width indent 72.It Ar address 73For the 74.Tn DARPA Ns -Internet 75family, 76the address is either a host name present in the host name data 77base, 78.Xr hosts 5 , 79or a 80.Tn DARPA 81Internet address expressed in the Internet standard 82.Dq dot notation . 83.\" For the Xerox Network Systems(tm) family, 84.\" addresses are 85.\" .Ar net:a.b.c.d.e.f , 86.\" where 87.\" .Ar net 88.\" is the assigned network number (in decimal), 89.\" and each of the six bytes of the host number, 90.\" .Ar a 91.\" through 92.\" .Ar f , 93.\" are specified in hexadecimal. 94.\" The host number may be omitted on 10Mb/s Ethernet interfaces, 95.\" which use the hardware physical address, 96.\" and on interfaces other than the first. 97.\" For the 98.\" .Tn ISO 99.\" family, addresses are specified as a long hexadecimal string, 100.\" as in the Xerox family. However, two consecutive dots imply a zero 101.\" byte, and the dots are optional, if the user wishes to (carefully) 102.\" count out long strings of digits in network byte order. 103.It Ar address_family 104Specify the 105.Ar "address family" 106which affects interpretation of the remaining parameters. 107Since an interface can receive transmissions in differing protocols 108with different naming schemes, specifying the address family is recommended. 109The address or protocol families currently 110supported are 111.Dq inet , 112.Dq atalk , 113.\" .Dq iso , 114and 115.Dq ipx . 116.\" and 117.\" .Dq ns . 118.It Ar dest_address 119Specify the address of the correspondent on the other end 120of a point to point link. 121.It Ar interface 122This 123parameter is a string of the form 124.Dq name unit , 125for example, 126.Dq en0 . 127.El 128.Pp 129The following parameters may be set with 130.Nm ifconfig : 131.Bl -tag -width indent 132.It Cm alias 133Establish an additional network address for this interface. 134This is sometimes useful when changing network numbers, and 135one wishes to accept packets addressed to the old interface. 136.It Cm arp 137Enable the use of the Address Resolution Protocol in mapping 138between network level addresses and link level addresses (default). 139This is currently implemented for mapping between 140.Tn DARPA 141Internet 142addresses and 10Mb/s Ethernet addresses. 143.It Fl arp 144Disable the use of the Address Resolution Protocol. 145.It Cm broadcast 146(Inet only) 147Specify the address to use to represent broadcasts to the 148network. 149The default broadcast address is the address with a host part of all 1's. 150.It Cm debug 151Enable driver dependent debugging code; usually, this turns on 152extra console error logging. 153.It Fl debug 154Disable driver dependent debugging code. 155.It Cm delete 156Remove the network address specified. 157This would be used if you incorrectly specified an alias, or it 158was no longer needed. 159If you have incorrectly set an NS address having the side effect 160of specifying the host portion, removing all NS addresses will 161allow you to respecify the host portion. 162.It Cm down 163Mark an interface ``down''. When an interface is 164marked ``down'', the system will not attempt to 165transmit messages through that interface. 166If possible, the interface will be reset to disable reception as well. 167This action does not automatically disable routes using the interface. 168.\" .It Cm ipdst 169.\" This is used to specify an Internet host who is willing to receive 170.\" ip packets encapsulating NS packets bound for a remote network. 171.\" An apparent point to point link is constructed, and 172.\" the address specified will be taken as the NS address and network 173.\" of the destination. 174.\" IP encapsulation of 175.\" .Tn CLNP 176.\" packets is done differently. 177.It Cm media Ar type 178If the driver supports the media selection system, set the media type 179of the interface to 180.Ar type . 181Some interfaces support the mutually exclusive use of one of several 182different physical media connectors. For example, a 10Mb/s Ethernet 183interface might support the use of either 184.Tn AUI 185or twisted pair connectors. Setting the media type to 186.Dq 10base5/AUI 187would change the currently active connector to the AUI port. 188Setting it to 189.Dq 10baseT/UTP 190would activate twisted pair. Refer to the interfaces' driver 191specific documentation or man page for a complete list of the 192available types. 193.It Cm mediaopt Ar opts 194If the driver supports the media selection system, set the specified 195media options on the interface. 196.Ar Opts 197is a comma delimited list of options to apply to the interface. 198Refer to the interfaces' driver specific man page for a complete 199list of available options. 200.It Fl mediaopt Ar opts 201If the driver supports the media selection system, disable the 202specified media options on the interface. 203.It Cm metric Ar n 204Set the routing metric of the interface to 205.Ar n , 206default 0. 207The routing metric is used by the routing protocol 208.Pq Xr routed 8 . 209Higher metrics have the effect of making a route 210less favorable; metrics are counted as addition hops 211to the destination network or host. 212.It Cm mtu Ar n 213Set the maximum transmission unit of the interface to 214.Ar n , 215default is interface specific. 216The mtu is used to limit the size of packets that are transmitted on an 217interface. 218Not all interfaces support setting the mtu, and some interfaces have 219range restrictions. 220.It Cm netmask Ar mask 221.\" (Inet and ISO) 222(Inet only) 223Specify how much of the address to reserve for subdividing 224networks into sub-networks. 225The mask includes the network part of the local address 226and the subnet part, which is taken from the host field of the address. 227The mask can be specified as a single hexadecimal number 228with a leading 0x, with a dot-notation Internet address, 229or with a pseudo-network name listed in the network table 230.Xr networks 5 . 231The mask contains 1's for the bit positions in the 32-bit address 232which are to be used for the network and subnet parts, 233and 0's for the host part. 234The mask should contain at least the standard network portion, 235and the subnet field should be contiguous with the network 236portion. 237.\" see 238.\" Xr eon 5 . 239.\" .It Cm nsellength Ar n 240.\" .Pf ( Tn ISO 241.\" only) 242.\" This specifies a trailing number of bytes for a received 243.\" .Tn NSAP 244.\" used for local identification, the remaining leading part of which is 245.\" taken to be the 246.\" .Tn NET 247.\" (Network Entity Title). 248.\" The default value is 1, which is conformant to US 249.\" .Tn GOSIP . 250.\" When an ISO address is set in an ifconfig command, 251.\" it is really the 252.\" .Tn NSAP 253.\" which is being specified. 254.\" For example, in 255.\" .Tn US GOSIP , 256.\" 20 hex digits should be 257.\" specified in the 258.\" .Tn ISO NSAP 259.\" to be assigned to the interface. 260.\" There is some evidence that a number different from 1 may be useful 261.\" for 262.\" .Tn AFI 263.\" 37 type addresses. 264.It Cm range 265Under appletalk, set the interface to respond to a 266.Em netrange. 267of the form startnet-endnet. Appletalk uses this scheme instead of 268netmasks though 269.Bx Free 270implements 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 285.Dq up . 286This may be used to enable an interface after an 287.Dq ifconfig down . 288It happens automatically when setting the first address on an interface. 289If the interface was reset when previously marked down, 290the hardware will be re-initialized. 291.El 292.Pp 293.Nm Ifconfig 294displays the current configuration for a network interface 295when no optional parameters are supplied. 296If a protocol family is specified, 297.Nm 298will report only the details specific to that protocol family. 299.Pp 300If the driver does supports the media selection system, the supported 301media list will be included in the output. 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. 308The 309.Fl d 310flag limits this to interfaces that are down, and 311.Fl u 312limits this to interfaces that are up. 313.Pp 314The 315.Fl l 316flag may be used to list all available interfaces on the system, with 317no other additional information. Use of this flag is mutually exclusive 318with all other flags and commands, except for 319.Fl d 320(only list interfaces that are down) 321and 322.Fl u 323(only list interfaces that are up). 324.Pp 325Only the super-user may modify the configuration of a network interface. 326.Sh NOTES 327The media selection system is relatively new and only some drivers support 328it (or have need for it). 329.Sh DIAGNOSTICS 330Messages indicating the specified interface does not exist, the 331requested address is unknown, or the user is not privileged and 332tried to alter an interface's configuration. 333.Sh SEE ALSO 334.Xr netstat 1 , 335.Xr netintro 4 , 336.Xr rc 8 , 337.Xr routed 8 338.\" .Xr eon 5 339.Sh HISTORY 340The 341.Nm 342command appeared in 343.Bx 4.2 . 344