ifconfig.tproj/ifconfig.8

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  32 .\"     From: @(#)ifconfig.8    8.3 (Berkeley) 1/5/94
  33 .\" $FreeBSD: src/sbin/ifconfig/ifconfig.8,v 1.27.2.14 2001/08/23 06:35:38 yar Exp $
  34 .\"
  35 .Dd July 2, 2001
  36 .Dt IFCONFIG 8
  37 .Os
  38 .Sh NAME
  39 .Nm ifconfig
  40 .Nd configure network interface parameters
  41 .Sh SYNOPSIS
  42 .Nm
  43 .Op Fl L
  44 .Op Fl m
  45 .Ar interface
  46 .Op Cm create
  47 .Op Ar address_family
  48 .Oo
  49 .Ar address Ns Op Cm / Ns Ar prefixlength
  50 .Op Ar dest_address
  51 .Oc
  52 .Op Ar parameters
  53 .Nm
  54 .Ar interface
  55 .Cm destroy
  56 .Nm
  57 .Fl a
  58 .Op Fl L
  59 .Op Fl d
  60 .Op Fl m
  61 .Op Fl u
  62 .Op Ar address_family
  63 .Nm
  64 .Fl l
  65 .Op Fl d
  66 .Op Fl u
  67 .Op Ar address_family
  68 .Nm
  69 .Op Fl L
  70 .Op Fl d
  71 .Op Fl m
  72 .Op Fl u
  73 .Op Fl C
  74 .Sh DESCRIPTION
  75 .Nm Ifconfig
  76 is used to assign an address
  77 to a network interface and/or configure
  78 network interface parameters.
  79 .Nm Ifconfig
  80 must be used at boot time to define the network address
  81 of each interface present on a machine; it may also be used at
  82 a later time to redefine an interface's address
  83 or other operating parameters.
  84 .Pp
  85 The following options are available:
  86 .Bl -tag -width indent
  87 .It Ar address
  88 For the
  89 .Tn DARPA Ns -Internet
  90 family,
  91 the address is either a host name present in the host name data
  92 base,
  93 .Xr hosts 5 ,
  94 or a
  95 .Tn DARPA
  96 Internet address expressed in the Internet standard
  97 .Dq dot notation .
  98 .Pp
  99 It is also possible to use the CIDR notation (also known as the
 100 slash notation) to include the netmask.
 101 That is, one can specify an address like
 102 .Li 192.168.0.1/16 .
 103 .\" For the Xerox Network Systems(tm) family,
 104 .\" addresses are
 105 .\" .Ar net:a.b.c.d.e.f ,
 106 .\" where
 107 .\" .Ar net
 108 .\" is the assigned network number (in decimal),
 109 .\" and each of the six bytes of the host number,
 110 .\" .Ar a
 111 .\" through
 112 .\" .Ar f ,
 113 .\" are specified in hexadecimal.
 114 .\" The host number may be omitted on IEEE 802 protocol
 115 .\" (Ethernet, FDDI, and Token Ring) interfaces,
 116 .\" which use the hardware physical address,
 117 .\" and on interfaces other than the first.
 118 .\" For the
 119 .\" .Tn ISO
 120 .\" family, addresses are specified as a long hexadecimal string,
 121 .\" as in the Xerox family.
 122 .\" However, two consecutive dots imply a zero
 123 .\" byte, and the dots are optional, if the user wishes to (carefully)
 124 .\" count out long strings of digits in network byte order.
 125 .It Ar address_family
 126 Specify the
 127 address family
 128 which affects interpretation of the remaining parameters.
 129 Since an interface can receive transmissions in differing protocols
 130 with different naming schemes, specifying the address family is recommended.
 131 The address or protocol families currently
 132 supported are
 133 .Dq inet ,
 134 .Dq inet6 ,
 135 .\" and
 136 .\" .Dq ns .
 137 .It Ar dest_address
 138 Specify the address of the correspondent on the other end
 139 of a point to point link.
 140 .It Ar interface
 141 This
 142 parameter is a string of the form
 143 .Dq name unit ,
 144 for example,
 145 .Dq Li en0 .
 146 .El
 147 .Pp
 148 The following parameters may be set with
 149 .Nm :
 150 .Bl -tag -width indent
 151 .It Cm add
 152 Another name for the
 153 .Cm alias
 154 parameter.
 155 Introduced for compatibility
 156 with
 157 .Bsx .
 158 .It Cm alias
 159 Establish an additional network address for this interface.
 160 This is sometimes useful when changing network numbers, and
 161 one wishes to accept packets addressed to the old interface.
 162 If the address is on the same subnet as the first network address
 163 for this interface, a netmask of
 164 .Li 0xffffffff
 165 has to be specified.
 166 .It Fl alias
 167 Remove the network address specified.
 168 This would be used if you incorrectly specified an alias, or it
 169 was no longer needed.
 170 If you have incorrectly set an NS address having the side effect
 171 of specifying the host portion, removing all NS addresses will
 172 allow you to respecify the host portion.
 173 .It Cm anycast
 174 (Inet6 only.)
 175 Specify that the address configured is an anycast address.
 176 Based on the current specification,
 177 only routers may configure anycast addresses.
 178 Anycast address will not be used as source address of any of outgoing
 179 IPv6 packets.
 180 .It Cm arp
 181 Enable the use of the Address Resolution Protocol
 182 .Pq Xr arp 4
 183 in mapping
 184 between network level addresses and link level addresses (default).
 185 This is currently implemented for mapping between
 186 .Tn DARPA
 187 Internet
 188 addresses and
 189 .Tn IEEE
 190 802 48-bit MAC addresses (Ethernet, FDDI, and Token Ring addresses).
 191 .It Fl arp
 192 Disable the use of the Address Resolution Protocol
 193 .Pq Xr arp 4 .
 194 .It Cm broadcast
 195 (Inet only.)
 196 Specify the address to use to represent broadcasts to the
 197 network.
 198 The default broadcast address is the address with a host part of all 1's.
 199 .It Cm debug
 200 Enable driver dependent debugging code; usually, this turns on
 201 extra console error logging.
 202 .It Fl debug
 203 Disable driver dependent debugging code.
 204 .It Cm delete
 205 Another name for the
 206 .Fl alias
 207 parameter.
 208 .It Cm down
 209 Mark an interface
 210 .Dq down .
 211 When an interface is marked
 212 .Dq down ,
 213 the system will not attempt to
 214 transmit messages through that interface.
 215 If possible, the interface will be reset to disable reception as well.
 216 This action does not automatically disable routes using the interface.
 217 .It Cm ether
 218 Another name for the
 219 .Cm lladdr
 220 parameter.
 221 .\" .It Cm ipdst
 222 .\" This is used to specify an Internet host who is willing to receive
 223 .\" ip packets encapsulating NS packets bound for a remote network.
 224 .\" An apparent point to point link is constructed, and
 225 .\" the address specified will be taken as the NS address and network
 226 .\" of the destination.
 227 .\" IP encapsulation of
 228 .\" .Tn CLNP
 229 .\" packets is done differently.
 230 .It Cm lladdr Ar addr
 231 Set the link-level address on an interface.
 232 This can be used to
 233 e.g. set a new MAC address on an ethernet interface, though the
 234 mechanism used is not ethernet-specific.
 235 The address
 236 .Ar addr
 237 is specified as a series of colon-separated hex digits.
 238 If the interface is already
 239 up when this option is used, it will be briefly brought down and
 240 then brought back up again in order to ensure that the receive
 241 filter in the underlying ethernet hardware is properly reprogrammed.
 242 .It Cm media Ar type
 243 If the driver supports the media selection system, set the media type
 244 of the interface to
 245 .Ar type .
 246 Some interfaces support the mutually exclusive use of one of several
 247 different physical media connectors.
 248 For example, a 10Mb/s Ethernet
 249 interface might support the use of either
 250 .Tn AUI
 251 or twisted pair connectors.
 252 Setting the media type to
 253 .Dq 10base5/AUI
 254 would change the currently active connector to the AUI port.
 255 Setting it to
 256 .Dq 10baseT/UTP
 257 would activate twisted pair.
 258 Refer to the interfaces' driver
 259 specific documentation or man page for a complete list of the
 260 available types.
 261 .It Cm mediaopt Ar opts
 262 If the driver supports the media selection system, set the specified
 263 media options on the interface.
 264 The
 265 .Ar opts
 266 argument
 267 is a comma delimited list of options to apply to the interface.
 268 Refer to the interfaces' driver specific man page for a complete
 269 list of available options.
 270 .It Fl mediaopt Ar opts
 271 If the driver supports the media selection system, disable the
 272 specified media options on the interface.
 273 .It Cm tunnel Ar src_addr dest_addr
 274 (IP tunnel devices only.)
 275 Configure the physical source and destination address for IP tunnel
 276 interfaces
 277 .Pq Xr gif 4 .
 278 The arguments
 279 .Ar src_addr
 280 and
 281 .Ar dest_addr
 282 are interpreted as the outer source/destination for the encapsulating
 283 IPv4/IPv6 header.
 284 .It Cm deletetunnel
 285 Unconfigure the physical source and destination address for IP tunnel
 286 interfaces previously configured with
 287 .Cm tunnel .
 288 .It Cm create
 289 Create the specified network pseudo-device.
 290 If the interface is given without a unit number, try to create a new
 291 device with an arbitrary unit number.
 292 If creation of an arbitrary device is sucessful, the new device name is
 293 printed to standard output.
 294 .It Cm destroy
 295 Destroy the specified network pseudo-device.
 296 .It Cm plumb
 297 Another name for the
 298 .Cm create
 299 parameter.
 300 Included for
 301 .Tn Solaris
 302 compatibility.
 303 .It Cm unplumb
 304 Another name for the
 305 .Cm destroy
 306 parameter.
 307 Included for
 308 .Tn Solaris
 309 compatibility.
 310 .It Cm metric Ar n
 311 Set the routing metric of the interface to
 312 .Ar n ,
 313 default 0.
 314 The routing metric is used by the routing protocol
 315 .Pq Xr routed 8 .
 316 Higher metrics have the effect of making a route
 317 less favorable; metrics are counted as addition hops
 318 to the destination network or host.
 319 .It Cm mtu Ar n
 320 Set the maximum transmission unit of the interface to
 321 .Ar n ,
 322 default is interface specific.
 323 The MTU is used to limit the size of packets that are transmitted on an
 324 interface.
 325 Not all interfaces support setting the MTU, and some interfaces have
 326 range restrictions.
 327 .It Cm netmask Ar mask
 328 .\" (Inet and ISO.)
 329 (Inet only.)
 330 Specify how much of the address to reserve for subdividing
 331 networks into sub-networks.
 332 The mask includes the network part of the local address
 333 and the subnet part, which is taken from the host field of the address.
 334 The mask can be specified as a single hexadecimal number
 335 with a leading
 336 .Ql 0x ,
 337 with a dot-notation Internet address,
 338 or with a pseudo-network name listed in the network table
 339 .Xr networks 5 .
 340 The mask contains 1's for the bit positions in the 32-bit address
 341 which are to be used for the network and subnet parts,
 342 and 0's for the host part.
 343 The mask should contain at least the standard network portion,
 344 and the subnet field should be contiguous with the network
 345 portion.
 346 .Pp
 347 The netmask can also be specified in CIDR notation after the address.
 348 See the
 349 .Ar address
 350 option above for more information.
 351 .It Cm prefixlen Ar len
 352 (Inet6 only.)
 353 Specify that
 354 .Ar len
 355 bits are reserved for subdividing networks into sub-networks.
 356 The
 357 .Ar len
 358 must be integer, and for syntactical reason it must be between 0 to 128.
 359 It is almost always 64 under the current IPv6 assignment rule.
 360 If the parameter is omitted, 64 is used.
 361 .\" see
 362 .\" Xr eon 5 .
 363 .\" .It Cm nsellength Ar n
 364 .\" .Pf ( Tn ISO
 365 .\" only)
 366 .\" This specifies a trailing number of bytes for a received
 367 .\" .Tn NSAP
 368 .\" used for local identification, the remaining leading part of which is
 369 .\" taken to be the
 370 .\" .Tn NET
 371 .\" (Network Entity Title).
 372 .\" The default value is 1, which is conformant to US
 373 .\" .Tn GOSIP .
 374 .\" When an ISO address is set in an ifconfig command,
 375 .\" it is really the
 376 .\" .Tn NSAP
 377 .\" which is being specified.
 378 .\" For example, in
 379 .\" .Tn US GOSIP ,
 380 .\" 20 hex digits should be
 381 .\" specified in the
 382 .\" .Tn ISO NSAP
 383 .\" to be assigned to the interface.
 384 .\" There is some evidence that a number different from 1 may be useful
 385 .\" for
 386 .\" .Tn AFI
 387 .\" 37 type addresses.
 388 .It Cm remove
 389 Another name for the
 390 .Fl alias
 391 parameter.
 392 Introduced for compatibility
 393 with
 394 .Bsx .
 395 .Sm off
 396 .It Cm link Op Cm 0 No - Cm 2
 397 .Sm on
 398 Enable special processing of the link level of the interface.
 399 These three options are interface specific in actual effect, however,
 400 they are in general used to select special modes of operation.
 401 An example
 402 of this is to enable SLIP compression, or to select the connector type
 403 for some Ethernet cards.
 404 Refer to the man page for the specific driver
 405 for more information.
 406 .Sm off
 407 .It Fl link Op Cm 0 No - Cm 2
 408 .Sm on
 409 Disable special processing at the link level with the specified interface.
 410 .It Cm up
 411 Mark an interface
 412 .Dq up .
 413 This may be used to enable an interface after an
 414 .Dq Nm Cm down .
 415 It happens automatically when setting the first address on an interface.
 416 If the interface was reset when previously marked down,
 417 the hardware will be re-initialized.
 418 .El
 419 .Pp
 420 .Nm Ifconfig
 421 displays the current configuration for a network interface
 422 when no optional parameters are supplied.
 423 If a protocol family is specified,
 424 .Nm
 425 will report only the details specific to that protocol family.
 426 .Pp
 427 If the driver does supports the media selection system, the supported
 428 media list will be included in the output.
 429 .Pp
 430 If the
 431 .Fl m
 432 flag is passed before an interface name,
 433 .Nm
 434 will display all
 435 of the supported media for the specified interface.
 436 If
 437 .Fl L
 438 flag is supplied, address lifetime is displayed for IPv6 addresses,
 439 as time offset string.
 440 .Pp
 441 Optionally, the
 442 .Fl a
 443 flag may be used instead of an interface name.
 444 This flag instructs
 445 .Nm
 446 to display information about all interfaces in the system.
 447 The
 448 .Fl d
 449 flag limits this to interfaces that are down, and
 450 .Fl u
 451 limits this to interfaces that are up.
 452 When no arguments are given,
 453 .Fl a
 454 is implied.
 455 .Pp
 456 The
 457 .Fl l
 458 flag may be used to list all available interfaces on the system, with
 459 no other additional information.
 460 Use of this flag is mutually exclusive
 461 with all other flags and commands, except for
 462 .Fl d
 463 (only list interfaces that are down)
 464 and
 465 .Fl u
 466 (only list interfaces that are up).
 467 .Pp
 468 The
 469 .Fl C
 470 flag may be used to list all of the interface cloners available on
 471 the system, with no additional information.
 472 Use of this flag is mutually exclusive with all other flags and commands.
 473 .Pp
 474 Only the super-user may modify the configuration of a network interface.
 475 .Sh NOTES
 476 The media selection system is relatively new and only some drivers support
 477 it (or have need for it).
 478 .Sh DIAGNOSTICS
 479 Messages indicating the specified interface does not exist, the
 480 requested address is unknown, or the user is not privileged and
 481 tried to alter an interface's configuration.
 482 .Sh BUGS
 483 IPv6 link-local addresses are required for several basic communication
 484 between IPv6 node.
 485 If they are deleted by
 486 .Nm
 487 manually, the kernel might show very strange behavior.
 488 So, such manual deletions are strongly discouraged.
 489 .Sh SEE ALSO
 490 .Xr netstat 1 ,
 491 .Xr netintro 4 ,
 492 .\" .Xr eon 5 ,
 493 .Xr rc 8 ,
 494 .Xr routed 8
 495 .Sh HISTORY
 496 The
 497 .Nm
 498 command appeared in
 499 .Bx 4.2 .