1.\" $NetBSD: ifconfig.8,v 1.21 1997/10/11 02:44:36 enami 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. All advertising materials mentioning features or use of this software 15.\" must display the following acknowledgement: 16.\" This product includes software developed by the University of 17.\" California, Berkeley and its contributors. 18.\" 4. Neither the name of the University nor the names of its contributors 19.\" may be used to endorse or promote products derived from this software 20.\" without specific prior written permission. 21.\" 22.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 23.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 24.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 25.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 26.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 27.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 28.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 29.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 30.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 31.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 32.\" SUCH DAMAGE. 33.\" 34.\" @(#)ifconfig.8 8.4 (Berkeley) 6/1/94 35.\" 36.Dd April 16, 1997 37.Dt IFCONFIG 8 38.Os BSD 4.2 39.Sh NAME 40.Nm ifconfig 41.Nd configure network interface parameters 42.Sh SYNOPSIS 43.Nm 44.Ar interface address_family 45.Oo 46.Ar address 47.Op Ar dest_address 48.Oc 49.Op Ar parameters 50.Nm "" 51.Op Fl m 52.Ar interface 53.Op Ar protocol_family 54.Nm "" 55.Fl a 56.Op Fl m 57.Op Fl d 58.Op Fl u 59.Op Ar protocol_family 60.Nm "" 61.Fl l 62.Op Fl d 63.Op Fl u 64.Sh DESCRIPTION 65.Nm 66is used to assign an address 67to a network interface and/or configure 68network interface parameters. 69.Nm 70must be used at boot time to define the network address 71of each interface present on a machine; it may also be used at 72a later time to redefine an interface's address 73or other operating parameters. 74.Pp 75Available operands for 76.Nm "" : 77.Bl -tag -width Ds 78.It Ar Address 79For the 80.Tn DARPA-Internet 81family, 82the address is either a host name present in the host name data 83base, 84.Xr hosts 5 , 85or a 86.Tn DARPA 87Internet address expressed in the Internet standard 88.Dq dot notation . 89For the Xerox Network Systems(tm) family, 90addresses are 91.Ar net:a.b.c.d.e.f , 92where 93.Ar net 94is the assigned network number (in decimal), 95and each of the six bytes of the host number, 96.Ar a 97through 98.Ar f , 99are specified in hexadecimal. 100The host number may be omitted on 10Mb/s Ethernet interfaces, 101which use the hardware physical address, 102and on interfaces other than the first. 103For the 104.Tn ISO 105family, addresses are specified as a long hexadecimal string, 106as in the Xerox family. However, two consecutive dots imply a zero 107byte, and the dots are optional, if the user wishes to (carefully) 108count out long strings of digits in network byte order. 109.It Ar address_family 110Specifies the 111.Ar address family 112which affects interpretation of the remaining parameters. 113Since an interface can receive transmissions in differing protocols 114with different naming schemes, specifying the address family is recommended. 115The address or protocol families currently 116supported are 117.Dq inet , 118.Dq atalk , 119.Dq iso , 120and 121.Dq ns . 122.It Ar Interface 123The 124.Ar interface 125parameter is a string of the form 126.Dq name unit , 127for example, 128.Dq en0 129.El 130.Pp 131The following parameters may be set with 132.Nm "" : 133.Bl -tag -width dest_addressxx 134.It Cm alias 135Establish an additional network address for this interface. 136This is sometimes useful when changing network numbers, and 137one wishes to accept packets addressed to the old interface. 138.It Cm arp 139Enable the use of the Address Resolution Protocol in mapping 140between network level addresses and link level addresses (default). 141This is currently implemented for mapping between 142.Tn DARPA 143Internet 144addresses and 10Mb/s Ethernet addresses. 145.It Fl arp 146Disable the use of the Address Resolution Protocol. 147.It Cm broadcast Ar mask 148(Inet only) 149Specify the address to use to represent broadcasts to the 150network. 151The default broadcast address is the address with a host part of all 1's. 152.It Cm debug 153Enable driver dependent debugging code; usually, this turns on 154extra console error logging. 155.It Fl debug 156Disable driver dependent debugging code. 157.ne 1i 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 175This is used to specify an Internet host who is willing to receive 176ip packets encapsulating NS packets bound for a remote network. 177An apparent point to point link is constructed, and 178the address specified will be taken as the NS address and network 179of the destination. 180IP encapsulation of 181.Tn CLNP 182packets 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 . 217Most interfaces don't support this option. 218.It Cm netmask Ar mask 219(Inet and ISO) 220Specify how much of the address to reserve for subdividing 221networks into sub-networks. 222The mask includes the network part of the local address 223and the subnet part, which is taken from the host field of the address. 224The mask can be specified as a single hexadecimal number 225with a leading 0x, with a dot-notation Internet address, 226or with a pseudo-network name listed in the network table 227.Xr networks 5 . 228The mask contains 1's for the bit positions in the 32-bit address 229which are to be used for the network and subnet parts, 230and 0's for the host part. 231The mask should contain at least the standard network portion, 232and the subnet field should be contiguous with the network 233portion. 234.\" see 235.\" Xr eon 5 . 236.It Cm nsellength Ar n 237.Pf ( Tn ISO 238only) 239This specifies a trailing number of bytes for a received 240.Tn NSAP 241used for local identification, the remaining leading part of which is 242taken to be the 243.Tn NET 244(Network Entity Title). 245The default value is 1, which is conformant to US 246.Tn GOSIP . 247When an ISO address is set in an ifconfig command, 248it is really the 249.Tn NSAP 250which is being specified. 251For example, in 252.Tn US GOSIP , 25320 hex digits should be 254specified in the 255.Tn ISO NSAP 256to be assigned to the interface. 257There is some evidence that a number different from 1 may be useful 258for 259.Tn AFI 26037 type addresses. 261.It Cm trailers 262Request the use of a ``trailer'' link level encapsulation when 263sending (default). 264If a network interface supports 265.Cm trailers , 266the system will, when possible, encapsulate outgoing 267messages in a manner which minimizes the number of 268memory to memory copy operations performed by the receiver. 269On networks that support the Address Resolution Protocol (see 270.Xr arp 4 ; 271currently, only 10 Mb/s Ethernet), 272this flag indicates that the system should request that other 273systems use trailers when sending to this host. 274Similarly, trailer encapsulations will be sent to other 275hosts that have made such requests. 276Currently used by Internet protocols only. 277.It Fl trailers 278Disable the use of a ``trailer'' link level encapsulation. 279.It Cm link[0-2] 280Enable special processing of the link level of the interface. 281These three options are interface specific in actual effect, however, 282they are in general used to select special modes of operation. An example 283of this is to enable SLIP compression, or to select the connector type 284for some ethernet cards. Refer to the man page for the specific driver 285for more information. 286.ne 1i 287.It Fl link[0-2] 288Disable special processing at the link level with the specified interface. 289.It Cm up 290Mark an interface ``up''. 291This may be used to enable an interface after an ``ifconfig down.'' 292It happens automatically when setting the first address on an interface. 293If the interface was reset when previously marked down, 294the hardware will be re-initialized. 295.El 296.Pp 297.Nm 298displays the current configuration for a network interface 299when no optional parameters are supplied. 300If a protocol family is specified, 301Ifconfig will report only the details specific to that protocol family. 302.Pp 303If the 304.Fl m 305flag is passed before an interface name, 306.Nm 307will display all of the supported media for the specified interface. 308.Pp 309Optionally, the 310.Fl a 311flag may be used instead of an interface name. This flag instructs 312.Nm 313to display information about all interfaces in the system. 314.Fl d 315limits this to interfaces that are down, and 316.Fl u 317limits this to interfaces that are up. 318.Pp 319The 320.Fl l 321flag may be used to list all available interfaces on the system, with 322no other additional information. Use of this flag is mutually exclusive 323with all other flags and commands, except for 324.Fl d 325(only list interfaces that are down) 326and 327.Fl u 328(only list interfaces that are up). 329.Pp 330Only the super-user may modify the configuration of a network interface. 331.Sh DIAGNOSTICS 332Messages indicating the specified interface does not exit, the 333requested address is unknown, or the user is not privileged and 334tried to alter an interface's configuration. 335.Sh SEE ALSO 336.Xr netstat 1 , 337.Xr netintro 4 , 338.Xr rc 8 , 339.Xr routed 8 , 340.\" .Xr eon 5 341.Sh HISTORY 342The 343.Nm 344command appeared in 345.Bx 4.2 . 346