Skip site navigation (1)Skip section navigation (2)

FreeBSD Man Pages

Man Page or Keyword Search:
Man Architecture
Apropos Keyword Search (all sections) Output format
home | help
IFCONFIG(8)             FreeBSD System Manager's Manual            IFCONFIG(8)

NAME
     ifconfig - configure network interface parameters

SYNOPSIS
     ifconfig [-L] [-k] [-m] [-n] interface [create] [address_family] [address
              [dest_address]] [parameters]
     ifconfig interface destroy
     ifconfig -a [-L] [-d] [-m] [-u] [-v] [address_family]
     ifconfig -l [-d] [-u] [address_family]
     ifconfig [-L] [-d] [-k] [-m] [-u] [-v] [-C]
     ifconfig [-g groupname]

DESCRIPTION
     The ifconfig utility is used to assign an address to a network interface
     and/or configure network interface parameters.  The ifconfig utility must
     be used at boot time to define the network address of each interface
     present on a machine; it may also be used at a later time to redefine an
     interface's address or other operating parameters.

     The following options are available:

     address
             For the DARPA-Internet family, the address is either a host name
             present in the host name data base, hosts(5), or a DARPA Internet
             address expressed in the Internet standard ``dot notation''.

             It is also possible to use the CIDR notation (also known as the
             slash notation) to include the netmask.  That is, one can specify
             an address like 192.168.0.1/16.

             For ``inet6'' family, it is also possible to specify the prefix
             length using the slash notation, like ::1/128.  See the prefixlen
             parameter below for more information.

             The link-level (``link'') address is specified as a series of
             colon-separated hex digits.  This can be used to e.g. set a new
             MAC address on an ethernet interface, though the mechanism used
             is not ethernet-specific.  If the interface is already up when
             this option is used, it will be briefly brought down and then
             brought back up again in order to ensure that the receive filter
             in the underlying ethernet hardware is properly reprogrammed.

     address_family
             Specify the address family which affects interpretation of the
             remaining parameters.  Since an interface can receive
             transmissions in differing protocols with different naming
             schemes, specifying the address family is recommended.  The
             address or protocol families currently supported are ``inet'',
             ``inet6'', ``atalk'', ``ipx'', and ``link''.  The default is
             ``inet''.  ``ether'' and ``lladdr'' are synonyms for ``link''.

     dest_address
             Specify the address of the correspondent on the other end of a
             point to point link.

     interface
             This parameter is a string of the form ``name unit'', for
             example, ``ed0''.

     groupname
             List the interfaces in the given group.

     The following parameters may be set with ifconfig:

     add     Another name for the alias parameter.  Introduced for
             compatibility with BSD/OS.

     alias   Establish an additional network address for this interface.  This
             is sometimes useful when changing network numbers, and one wishes
             to accept packets addressed to the old interface.  If the address
             is on the same subnet as the first network address for this
             interface, a non-conflicting netmask must be given.  Usually
             0xffffffff is most appropriate.

     -alias  Remove the network address specified.  This would be used if you
             incorrectly specified an alias, or it was no longer needed.  If
             you have incorrectly set an NS address having the side effect of
             specifying the host portion, removing all NS addresses will allow
             you to respecify the host portion.

     anycast
             (Inet6 only.)  Specify that the address configured is an anycast
             address.  Based on the current specification, only routers may
             configure anycast addresses.  Anycast address will not be used as
             source address of any of outgoing IPv6 packets.

     arp     Enable the use of the Address Resolution Protocol (arp(4)) in
             mapping between network level addresses and link level addresses
             (default).  This is currently implemented for mapping between
             DARPA Internet addresses and IEEE 802 48-bit MAC addresses
             (Ethernet, FDDI, and Token Ring addresses).

     -arp    Disable the use of the Address Resolution Protocol (arp(4)).

     staticarp
             If the Address Resolution Protocol is enabled, the host will only
             reply to requests for its addresses, and will never send any
             requests.

     -staticarp
             If the Address Resolution Protocol is enabled, the host will
             perform normally, sending out requests and listening for replies.

     broadcast
             (Inet only.)  Specify the address to use to represent broadcasts
             to the network.  The default broadcast address is the address
             with a host part of all 1's.

     debug   Enable driver dependent debugging code; usually, this turns on
             extra console error logging.

     -debug  Disable driver dependent debugging code.

     promisc
             Put interface into permanently promiscuous mode.

     -promisc
             Disable permanently promiscuous mode.

     delete  Another name for the -alias parameter.

     down    Mark an interface ``down''.  When an interface is marked
             ``down'', the system will not attempt to transmit messages
             through that interface.  If possible, the interface will be reset
             to disable reception as well.  This action does not automatically
             disable routes using the interface.

     group group-name
             Assign the interface to a ``group''.  Any interface can be in
             multiple groups.

             Cloned interfaces are members of their interface family group by
             default.  For example, a PPP interface such as ppp0 is a member
             of the PPP interface family group, ppp.

     -group group-name
             Remove the interface from the given ``group''.

     eui64   (Inet6 only.)  Fill interface index (lowermost 64bit of an IPv6
             address) automatically.

     ipdst   This is used to specify an Internet host who is willing to
             receive IP packets encapsulating IPX packets bound for a remote
             network.  An apparent point to point link is constructed, and the
             address specified will be taken as the IPX address and network of
             the destination.

     maclabel label
             If Mandatory Access Control support is enabled in the kernel, set
             the MAC label to label.

     media type
             If the driver supports the media selection system, set the media
             type of the interface to type.  Some interfaces support the
             mutually exclusive use of one of several different physical media
             connectors.  For example, a 10Mbit/s Ethernet interface might
             support the use of either AUI or twisted pair connectors.
             Setting the media type to 10base5/AUI would change the currently
             active connector to the AUI port.  Setting it to 10baseT/UTP
             would activate twisted pair.  Refer to the interfaces' driver
             specific documentation or man page for a complete list of the
             available types.

     mediaopt opts
             If the driver supports the media selection system, set the
             specified media options on the interface.  The opts argument is a
             comma delimited list of options to apply to the interface.  Refer
             to the interfaces' driver specific man page for a complete list
             of available options.

     -mediaopt opts
             If the driver supports the media selection system, disable the
             specified media options on the interface.

     mode mode
             If the driver supports the media selection system, set the
             specified operating mode on the interface to mode.  For IEEE
             802.11 wireless interfaces that support multiple operating modes
             this directive is used to select between 802.11a (11a), 802.11b
             (11b), and 802.11g (11g) operating modes.

     inst minst, instance minst
             Set the media instance to minst.  This is useful for devices
             which have multiple physical layer interfaces (PHYs).

     name name
             Set the interface name to name.

     rxcsum, txcsum
             If the driver supports user-configurable checksum offloading,
             enable receive (or transmit) checksum offloading on the
             interface.  Some drivers may not be able to enable these flags
             independently of each other, so setting one may also set the
             other.  The driver will offload as much checksum work as it can
             reliably support, the exact level of offloading varies between
             drivers.

     -rxcsum, -txcsum
             If the driver supports user-configurable checksum offloading,
             disable receive (or transmit) checksum offloading on the
             interface.  These settings may not always be independent of each
             other.

     tso     If the driver supports tcp(4) segmentation offloading, enable TSO
             on the interface.  Some drivers may not be able to support TSO
             for ip(4) and ip6(4) packets, so they may enable only one of
             them.

     -tso    If the driver supports tcp(4) segmentation offloading, disable
             TSO on the interface.  It will always disable TSO for ip(4) and
             ip6(4).

     lro     If the driver supports tcp(4) large receive offloading, enable
             LRO on the interface.

     -lro    If the driver supports tcp(4) large receive offloading, disable
             LRO on the interface.

     vlanmtu, vlanhwtag
             If the driver offers user-configurable VLAN support, enable
             reception of extended frames or tag processing in hardware,
             respectively.  Note that this must be issued on a physical
             interface associated with vlan(4), not on a vlan(4) interface
             itself.

     -vlanmtu, -vlanhwtag
             If the driver offers user-configurable VLAN support, disable
             reception of extended frames or tag processing in hardware,
             respectively.

     polling
             Turn on polling(4) feature and disable interrupts on the
             interface, if driver supports this mode.

     -polling
             Turn off polling(4) feature and enable interrupt mode on the
             interface.

     create  Create the specified network pseudo-device.  If the interface is
             given without a unit number, try to create a new device with an
             arbitrary unit number.  If creation of an arbitrary device is
             successful, the new device name is printed to standard output
             unless the interface is renamed or destroyed in the same ifconfig
             invocation.

     destroy
             Destroy the specified network pseudo-device.

     plumb   Another name for the create parameter.  Included for Solaris
             compatibility.

     unplumb
             Another name for the destroy parameter.  Included for Solaris
             compatibility.

     metric n
             Set the routing metric of the interface to n, default 0.  The
             routing metric is used by the routing protocol (routed(8)).
             Higher metrics have the effect of making a route less favorable;
             metrics are counted as additional hops to the destination network
             or host.

     mtu n   Set the maximum transmission unit of the interface to n, default
             is interface specific.  The MTU is used to limit the size of
             packets that are transmitted on an interface.  Not all interfaces
             support setting the MTU, and some interfaces have range
             restrictions.

     netmask mask
             (Inet only.)  Specify how much of the address to reserve for
             subdividing networks into sub-networks.  The mask includes the
             network part of the local address and the subnet part, which is
             taken from the host field of the address.  The mask can be
             specified as a single hexadecimal number with a leading `0x',
             with a dot-notation Internet address, or with a pseudo-network
             name listed in the network table networks(5).  The mask contains
             1's for the bit positions in the 32-bit address which are to be
             used for the network and subnet parts, and 0's for the host part.
             The mask should contain at least the standard network portion,
             and the subnet field should be contiguous with the network
             portion.

             The netmask can also be specified in CIDR notation after the
             address.  See the address option above for more information.

     prefixlen len
             (Inet6 only.)  Specify that len bits are reserved for subdividing
             networks into sub-networks.  The len must be integer, and for
             syntactical reason it must be between 0 to 128.  It is almost
             always 64 under the current IPv6 assignment rule.  If the
             parameter is omitted, 64 is used.

             The prefix can also be specified using the slash notation after
             the address.  See the address option above for more information.

     range netrange
             Under appletalk, set the interface to respond to a netrange of
             the form startnet-endnet.  Appletalk uses this scheme instead of
             netmasks though FreeBSD implements it internally as a set of
             netmasks.

     remove  Another name for the -alias parameter.  Introduced for
             compatibility with BSD/OS.

     phase   The argument following this specifies the version (phase) of the
             Appletalk network attached to the interface.  Values of 1 or 2
             are permitted.

     link[0-2]
             Enable special processing of the link level of the interface.
             These three options are interface specific in actual effect,
             however, they are in general used to select special modes of
             operation.  An example of this is to enable SLIP compression, or
             to select the connector type for some Ethernet cards.  Refer to
             the man page for the specific driver for more information.

     -link[0-2]
             Disable special processing at the link level with the specified
             interface.

     monitor
             Put the interface in monitor mode.  No packets are transmitted,
             and received packets are discarded after bpf(4) processing.

     -monitor
             Take the interface out of monitor mode.

     up      Mark an interface ``up''.  This may be used to enable an
             interface after an ``ifconfig down''.  It happens automatically
             when setting the first address on an interface.  If the interface
             was reset when previously marked down, the hardware will be re-
             initialized.

     The following parameters are specific to IEEE 802.11 wireless interfaces:

     apbridge
             When operating as an access point, pass packets between wireless
             clients directly (default).  To instead let them pass up through
             the system and be forwarded using some other mechanism, use
             -apbridge.  Disabling the internal bridging is useful when
             traffic is to be processed with packet filtering.

     authmode mode
             Set the desired authentication mode in infrastructure mode.  Not
             all adaptors support all modes.  The set of valid modes is none,
             open, shared (shared key), 8021x (IEEE 802.1x), and wpa (IEEE
             WPA/WPA2/802.11i).  The 8021x and wpa modes are only useful when
             using an authentication service (a supplicant for client
             operation or an authenticator when operating as an access point).
             Modes are case insensitive.

     bgscan  Enable background scanning when operating as a station.
             Background scanning is a technique whereby a station associated
             to an access point will temporarily leave the channel to scan for
             neighboring stations.  This allows a station to maintain a cache
             of nearby access points so that roaming between access points can
             be done without a lengthy scan operation.  Background scanning is
             done only when a station is not busy and any outbound traffic
             will cancel a scan operation.  Background scanning should never
             cause packets to be lost though there may be some small latency
             if outbound traffic interrupts a scan operation.  By default
             background scanning is enabled if the device is capable.  To
             disable background scanning, use -bgscan.  Background scanning is
             controlled by the bgscanidle and bgscanintvl parameters.
             Background scanning must be enabled for roaming; this is an
             artifact of the current implementation and may not be required in
             the future.

     bgscanidle idletime
             Set the minimum time a station must be idle (not transmitting or
             receiving frames) before a background scan is initiated.  The
             idletime parameter is specified in milliseconds.  By default a
             station must be idle at least 250 milliseconds before a
             background scan is initiated.  The idle time may not be set to
             less than 100 milliseconds.

     bgscanintvl interval
             Set the interval at which background scanning is attempted.  The
             interval parameter is specified in seconds.  By default a
             background scan is considered every 300 seconds (5 minutes).  The
             interval may not be set to less than 15 seconds.

     bintval interval
             Set the interval at which beacon frames are sent when operating
             in ad-hoc or ap mode.  The interval parameter is specified in
             TU's (1024 usecs).  By default beacon frames are transmitted
             every 100 TU's.

     bmissthreshold count
             Set the number of consecutive missed beacons at which the station
             will attempt to roam (i.e., search for a new access point).  The
             count parameter must be in the range 1 to 255; though the upper
             bound may be reduced according to device capabilities.  The
             default threshold is 7 consecutive missed beacons; but this may
             be overridden by the device driver.  Another name for the
             bmissthreshold parameter is bmiss.

     bssid address
             Specify the MAC address of the access point to use when operating
             as a station in a BSS network.  This overrides any automatic
             selection done by the system.  To disable a previously selected
             access point, supply any, none, or - for the address.  This
             option is useful when more than one access point uses the same
             SSID.  Another name for the bssid parameter is ap.

     burst   Enable packet bursting.  Packet bursting is a transmission
             technique whereby the wireless medium is acquired once to send
             multiple frames and the interframe spacing is reduced.  This
             technique can significantly increase throughput by reducing
             transmission overhead.  Packet bursting is supported by the
             802.11e QoS specification and some devices that do not support
             QoS may still be capable.  By default packet bursting is enabled
             if a device is capable of doing it.  To disable packet bursting,
             use -burst.

     chanlist channels
             Set the desired channels to use when scanning for access points,
             neighbors in an IBSS network, or looking for unoccupied channels
             when operating as an access point.  The set of channels is
             specified as a comma-separated list with each element in the list
             representing either a single channel number or a range of the
             form ``a-b''.  Channel numbers must be in the range 1 to 255 and
             be permissible according to the operating characteristics of the
             device.

     channel number
             Set a single desired channel.  Channels range from 1 to 255, but
             the exact selection available depends on the region your adaptor
             was manufactured for.  Setting the channel to 0, any, or - will
             give you the default for your adaptor.  Some adaptors ignore this
             setting unless you are in ad-hoc mode.  Alternatively the
             frequency, in megahertz, may be specified instead of the channel
             number.

             When there are several ways to use a channel the channel
             number/frequency may be appended with attributes to clarify.  For
             example, if a device is capable of operating on channel 6 with
             802.11n and 802.11g then one can specify that g-only use should
             be used by specifying ``6:g''.  Similarly the channel width can
             be specified by appending it with ``/''; e.g. ``6/40'' specifies
             a 40MHz wide channel, These attributes can be combined as in:
             ``6:ht/40''.  The full set of flags specified following a `:''
             are: a (802.11a), b (802.11b), d (Atheros Dynamic Turbo mode), g
             (802.11g), h or n (802.11n aka HT), s (Atheros Static Turbo
             mode), and t (Atheros Dynamic Turbo mode, or appended to ``st''
             and ``dt'').  The full set of channel widths following a '/' are:
             5 (5MHz aka quarter-rate channel), 10 (10MHz aka half-rate
             channel), 20 (20MHz mostly for use in specifying ht20), and 40
             (40MHz mostly for use in specifying ht40), In addition, a 40MHz
             HT channel specification may include the location of the
             extension channel by appending ``+'' or ``-'' for above and
             below, respectively; e.g. ``2437:ht/40+'' specifies 40MHz wide HT
             operation with the center channel at frequency 2437 and the
             extension channel above.

     doth    Enable inclusion of an 802.11h country information element in
             beacon frames transmitted when operating as an access point.  By
             default 802.11h is enabled if the device is capable.  To disable
             802.11h use -doth.

     deftxkey index
             Set the default key to use for transmission.  Typically this is
             only set when using WEP encryption.  The weptxkey is an alias for
             this request; it is provided for backwards compatibility.

     dtimperiod period
             Set the DTIM period for transmitting buffered multicast data
             frames when operating in ap mode.  The period specifies the
             number of beacon intervals between DTIM and must be in the range
             1 to 15.  By default DTIM is 1 (i.e., DTIM occurs at each
             beacon).

     dturbo  Enable the use of Atheros Dynamic Turbo mode when communicating
             with another Dynamic Turbo-capable station.  Dynamic Turbo mode
             is an Atheros-specific mechanism by which stations switch between
             normal 802.11 operation and a ``boosted'' mode in which a 40MHz
             wide channel is used for communication.  Stations using Dynamic
             Turbo mode operate boosted only when the channel is free of non-
             dturbo stations; when a non-dturbo station is identified on the
             channel all stations will automatically drop back to normal
             operation.  By default, Dynamic Turbo mode is not enabled, even
             if the device is capable.  Note that turbo mode (dynamic or
             static) is only allowed on some channels depending on the
             regulatory constraints; use the list chan command to identify the
             channels where turbo mode may be used.  To disable Dynamic Turbo
             mode use -dturbo.

     fragthreshold length
             Set the threshold for which transmitted frames are broken into
             fragments.  The length argument is the frame size in bytes and
             must be in the range 256 to 2346.  Setting length to 2346, any,
             or - disables transmit fragmentation.  Not all adaptors honor the
             fragmentation threshold.

     hidessid
             When operating as an access point, do not broadcast the SSID in
             beacon frames or respond to probe request frames unless they are
             directed to the ap (i.e., they include the ap's SSID).  By
             default, the SSID is included in beacon frames and undirected
             probe request frames are answered.  To re-enable the broadcast of
             the SSID etc., use -hidessid.

     ff      Enable the use of Atheros Fast Frames when communicating with
             another Fast Frames-capable station.  Fast Frames are an
             encapsulation technique by which two 802.3 frames are transmitted
             in a single 802.11 frame.  This can noticeably improve throughput
             but requires that the receiving station understand how to
             decapsulate the frame.  Fast frame use is negotiated using the
             Atheros 802.11 vendor-specific protocol extension so enabling use
             is safe when communicating with non-Atheros devices.  By default,
             use of fast frames is enabled if the device is capable.  To
             explicitly disable fast frames, use -ff.

     list active
             Display the list of channels available for use taking into
             account any restrictions set with the chanlist directive.  See
             the description of list chan for more information.

     list caps
             Display the adaptor's capabilities, including the operating modes
             supported.

     list chan
             Display the list of channels available for use.  Channels are
             shown with their IEEE channel number, equivalent frequency, and
             usage modes.  Channels identified as `11g' are also usable in
             `11b' mode.  Channels identified as `11a Turbo' may be used only
             for Atheros' Static Turbo mode (specified with mediaopt turbo).
             Channels marked with a `*' have a regulatory constraint that they
             be passively scanned.  This means a station is not permitted to
             transmit on the channel until it identifies the channel is being
             used for 802.11 communication; typically by hearing a beacon
             frame from an access point operating on the channel.  list freq
             is another way of requesting this information.  By default a
             compacted list of channels is displayed; if the -v option is
             specified then all channels are shown.

     list mac
             Display the current MAC Access Control List state.  Each address
             is prefixed with a character that indicates the current policy
             applied to it: `+' indicates the address is allowed access, `-'
             indicates the address is denied access, `*' indicates the address
             is present but the current policy open (so the ACL is not
             consulted).

     list scan
             Display the access points and/or ad-hoc neighbors located in the
             vicinity.  The -v flag may be used to display long SSIDs.  -v
             also causes received information elements to be displayed
             symbolicaly.  This information may be updated automatically by
             the adaptor and/or with a scan request or through background
             scanning.  list ap is another way of requesting this information.

     list sta
             When operating as an access point display the stations that are
             currently associated.  When operating in ad-hoc mode display
             stations identified as neighbors in the IBSS.  When operating in
             station mode display the access point.  Capabilities advertised
             by the stations are described under the scan request.  Depending
             on the capabilities of the stations the following flags can be
             included in the output:

             A    Authorized.  Indicates that the station is permitted to
                  send/receive data frames.

             E    Extended Rate Phy (ERP).  Indicates that the station is
                  operating in an 802.11g network using extended transmit
                  rates.

             H    High Throughput (HT).  Indicates that the station is using
                  MCS to send/receive frames.

             P    Power Save.  Indicates that the station is operating in
                  power save mode.

             Q    Quality of Service (QoS).  Indicates that the station is
                  using QoS encapsulation for data frame.  QoS encapsulation
                  is enabled only when WME mode is enabled.

             By default information elements received from associated stations
             are displayed in a short form; the -v flag causes this
             information to be displayed symbolicaly.

     list wme
             Display the current parameters to use when operating in WME mode.
             When WME mode is enabled for an adaptor this information will be
             displayed with the regular status; this command is mostly useful
             for examining parameters when WME mode is disabled.  See the
             description of the wme directive for information on the various
             parameters.

     mcastrate rate
             Set the rate for transmitting multicast/broadcast frames.  Rates
             are specified as megabits/second in decimal; e.g. 5.5 for 5.5
             Mb/s.  This rate should be valid for the current operating
             conditions; if an invalid rate is specified drivers are free to
             chose an appropriate rate.

     powersave
             Enable powersave operation.  When operating as a client, the
             station will conserve power by periodically turning off the radio
             and listening for messages from the access point telling it there
             are packets waiting.  The station must then retrieve the packets.
             Not all devices support power save operation as a client.  The
             802.11 specification requires that all access points support
             power save but some drivers do not.  Use -powersave to disable
             powersave operation when operating as a client.

     powersavesleep sleep
             Set the desired max powersave sleep time in TU's (1024 usecs).
             By default the max powersave sleep time is 100 TU's.

     protmode technique
             For interfaces operating in 802.11g, use the specified technique
             for protecting OFDM frames in a mixed 11b/11g network.  The set
             of valid techniques is off, cts (CTS to self), and rtscts
             (RTS/CTS).  Technique names are case insensitive.  Not all
             devices support cts as a protection technique.

     pureg   When operating as an access point in 802.11g mode allow only 11g-
             capable stations to associate (11b-only stations are not
             permitted to associate).  To allow both 11g and 11b-only stations
             to associate, use -pureg.

     roaming mode
             When operating as a station, control how the system will behave
             when communication with the current access point is broken.  The
             mode argument may be one of device (leave it to the hardware
             device to decide), auto (handle either in the device or the
             operating system--as appropriate), manual (do nothing until
             explicitly instructed).  By default, the device is left to handle
             this if it is capable; otherwise, the operating system will
             automatically attempt to reestablish communication.  Manual mode
             is used by applications such as wpa_supplicant(8) that want to
             control the selection of an access point.

     roam:rssi11a rssi
             Set the threshold for controlling roaming when operating in an
             802.11a BSS.  The rssi parameter specifies the receive signal
             strength in dBm units at which roaming should be considered.  If
             the current rssi drops below this setting and background scanning
             is enabled, then the system will check if a more desirable access
             point is available and switch over to it.  The current scan cache
             contents are used if they are considered valid according to the
             scanvalid parameter; otherwise a background scan operation is
             triggered before any selection occurs.  By default rssi is set to
             7 dBm.

     roam:rssi11b rssi
             Set the threshold for controlling roaming when operating in an
             802.11b-only BSS.  See roam:rssi11a for a description of this
             parameter.  By default rssi is set to 7 dBm.

     roam:rssi11g rssi
             Set the threshold for controlling roaming when operating in a
             (mixed) 802.11g BSS.  See roam:rssi11a for a description of this
             parameter.  By default rssi is set to 7 dBm.

     roam:rate11a rate
             Set the threshold for controlling roaming when operating in an
             802.11a BSS.  The rate parameter specifies the transmit rate in
             megabits at which roaming should be considered.  If the current
             transmit rate drops below this setting and background scanning is
             enabled, then the system will check if a more desirable access
             point is available and switch over to it.  The current scan cache
             contents are used if they are considered valid according to the
             scanvalid parameter; otherwise a background scan operation is
             triggered before any selection occurs.  By default rate is set to
             12 Mb/s.

     roam:rate11b rate
             Set the threshold for controlling roaming when operating in an
             802.11b-only BSS.  See roam:rate11a for a description of this
             parameter.  By default rate is set to 1 Mb/s.

     roam:rate11g rate
             Set the threshold for controlling roaming when operating in a
             (mixed) 802.11g BSS.  See roam:rate11a for a description of this
             parameter.  By default rate is set to 5 Mb/s.

     rtsthreshold length
             Set the threshold for which transmitted frames are preceded by
             transmission of an RTS control frame.  The length argument is the
             frame size in bytes and must be in the range 1 to 2346.  Setting
             length to 2346, any, or - disables transmission of RTS frames.
             Not all adaptors support setting the RTS threshold.

     ssid ssid
             Set the desired Service Set Identifier (aka network name).  The
             SSID is a string up to 32 characters in length and may be
             specified as either a normal string or in hexadecimal when
             preceded by `0x'.  Additionally, the SSID may be cleared by
             setting it to `-'.

     scan    Initiate a scan of neighboring stations, wait for it to complete,
             and display all stations found.  Only the super-user can initiate
             a scan.  Depending on the capabilities of the APs, the following
             flags can be included in the output:

             A    Channel Agility.  Indicates that the station support channel
                  hopping as described by the IEEE 802.11b specification.

             B    Packet Binary Convolution Code (PBCC).  A modulation
                  alternative to the standard OFDM method.

             C    Pollreq

             c    Pollable

             D    Direct Sequence Spread Spectrum (DSSSOFDM).  Indicates the
                  the station supports DSSS modulation.

             E    Extended Service Set (ESS).  Indicates that the station is
                  part of an infrastructure network (in contrast to an
                  IBSS/ad-hoc network).

             I    IBSS/ad-hoc network.  Indicates that the station is part of
                  an ad-hoc network (in contrast to an ESS network).

             P    Privacy.  Data confidentiality is required for all data
                  frames exchanged within the BSS.  This means that this BSS
                  requires the station to use cryptographic means such as WEP,
                  TKIP or AES-CCMP to encrypt/decrypt data frames being
                  exchanged with others.

             R    Robust Security Network (RSN).  Indicates that the station
                  supports the IEEE 802.11i authentication and key management
                  protocol.

             S    Short Preamble.  Indicates that the network is using short
                  preambles (defined in 802.11b High Rate/DSSS PHY, short
                  preamble utilizes a 56 bit sync field in contrast to a 128
                  bit field used in long preamble mode).

             s    Short slot time.  Indicates that the network is using a
                  short slot time.

             Interesting information elements captured from the neighboring
             stations are displayed at the end of each row.  Possible elements
             are: WME (station supports WME), WPA (station supports WPA), RSN
             (station supports 802.11i/RSN), HT (station supports 802.11n/HT
             communication), ATH (station supoprts Atheros protocol
             extensions), VEN (station supports unknown vendor-specific
             extensions).  If the -v flag is used the information element
             contents will be shown.

             The list scan request can be used to show recent scan results
             without initiating a new scan.

             The -v flag may be used to prevent the shortening of long SSIDs.

     scanvalid threshold
             Set the maximum time the scan cache contents are considered
             valid; i.e. will be used without first triggering a scan
             operation to refresh the data.  The threshold parameter is
             specified in seconds and defaults to 60 seconds.  The minimum
             setting for threshold is 10 seconds.  One should take care
             setting this threshold; if it is set too low then attempts to
             roam to another access point may trigger unnecessary background
             scan operations.

     stationname name
             Set the name of this station.  The station name is not part of
             the IEEE 802.11 protocol though some interfaces support it.  As
             such it only seems to be meaningful to identical or virtually
             identical equipment.  Setting the station name is identical in
             syntax to setting the SSID.

     txpower power
             Set the power used to transmit frames.  The power argument is
             specified in .5 dBm units.  Out of range values are truncated.
             Typically only a few discreet power settings are available and
             the driver will use the setting closest to the specified value.
             Not all adaptors support changing the transmit power.

     wepmode mode
             Set the desired WEP mode.  Not all adaptors support all modes.
             The set of valid modes is off, on, and mixed.  The mixed mode
             explicitly tells the adaptor to allow association with access
             points which allow both encrypted and unencrypted traffic.  On
             these adaptors, on means that the access point must only allow
             encrypted connections.  On other adaptors, on is generally
             another name for mixed.  Modes are case insensitive.

     weptxkey index
             Set the WEP key to be used for transmission.  This is the same as
             setting the default transmission key with deftxkey.

     wepkey key|index:key
             Set the selected WEP key.  If an index is not given, key 1 is
             set.  A WEP key will be either 5 or 13 characters (40 or 104
             bits) depending of the local network and the capabilities of the
             adaptor.  It may be specified either as a plain string or as a
             string of hexadecimal digits preceded by `0x'.  For maximum
             portability, hex keys are recommended; the mapping of text keys
             to WEP encryption is usually driver-specific.  In particular, the
             Windows drivers do this mapping differently to FreeBSD.  A key
             may be cleared by setting it to `-'.  If WEP is supported then
             there are at least four keys.  Some adaptors support more than
             four keys.  If that is the case, then the first four keys (1-4)
             will be the standard temporary keys and any others will be
             adaptor specific keys such as permanent keys stored in NVRAM.

     wme     Enable Wireless Multimedia Extensions (WME) support, if
             available, for the specified interface.  WME is a subset of the
             IEEE 802.11e standard to support the efficient communication of
             realtime and multimedia data.  To disable WME support, use -wme.

             The following parameters are meaningful only when WME support is
             in use.  Parameters are specified per-AC (Access Category) and
             split into those that are used by a station when acting as an
             access point and those for client stations in the BSS.  The
             latter are received from the access point and may not be changed
             (at the station).  The following Access Categories are
             recognized:

             AC_BE      (or BE) best effort delivery,
             AC_BK      (or BK) background traffic,
             AC_VI      (or VI) video traffic,
             AC_VO      (or VO) voice traffic.

             AC parameters are case-insensitive.  Traffic classification is
             done in the operating system using the vlan priority associated
             with data frames or the ToS (Type of Service) indication in IP-
             encapsulated frames.  If neither information is present, traffic
             is assigned to the Best Effort (BE) category.

             ack ac  Set the ACK policy for QoS transmissions by the local
                     station; this controls whether or not data frames
                     transmitted by a station require an ACK response from the
                     receiving station.  To disable waiting for an ACK use
                     -ack.  This parameter is applied only to the local
                     station.

             acm ac  Enable the Admission Control Mandatory (ACM) mechanism
                     for transmissions by the local station.  To disable the
                     ACM use -acm.  On stations in a BSS this parameter is
                     read-only and indicates the setting received from the
                     access point.  NB: ACM is not supported right now.

             aifs ac count
                     Set the Arbitration Inter Frame Spacing (AIFS) channel
                     access parameter to use for transmissions by the local
                     station.  On stations in a BSS this parameter is read-
                     only and indicates the setting received from the access
                     point.

             cwmin ac count
                     Set the CWmin channel access parameter to use for
                     transmissions by the local station.  On stations in a BSS
                     this parameter is read-only and indicates the setting
                     received from the access point.

             cwmax ac count
                     Set the CWmax channel access parameter to use for
                     transmissions by the local station.  On stations in a BSS
                     this parameter is read-only and indicates the setting
                     received from the access point.

             txoplimit ac limit
                     Set the Transmission Opportunity Limit channel access
                     parameter to use for transmissions by the local station.
                     This parameter defines an interval of time when a WME
                     station has the right to initiate transmissions onto the
                     wireless medium.  On stations in a BSS this parameter is
                     read-only and indicates the setting received from the
                     access point.

             bss:aifs ac count
                     Set the AIFS channel access parameter to send to stations
                     in a BSS.  This parameter is meaningful only when
                     operating in ap mode.

             bss:cwmin ac count
                     Set the CWmin channel access parameter to send to
                     stations in a BSS.  This parameter is meaningful only
                     when operating in ap mode.

             bss:cwmax ac count
                     Set the CWmax channel access parameter to send to
                     stations in a BSS.  This parameter is meaningful only
                     when operating in ap mode.

             bss:txoplimit ac limit
                     Set the TxOpLimit channel access parameter to send to
                     stations in a BSS.  This parameter is meaningful only
                     when operating in ap mode.

     The following parameters support an optional access control list feature
     available with some adaptors when operating in ap mode; see wlan_acl(4).
     This facility allows an access point to accept/deny association requests
     based on the MAC address of the station.  Note that this feature does not
     significantly enhance security as MAC address spoofing is easy to do.

     mac:add address
             Add the specified MAC address to the database.  Depending on the
             policy setting association requests from the specified station
             will be allowed or denied.

     mac:allow
             Set the ACL policy to permit association only by stations
             registered in the database.

     mac:del address
             Delete the specified MAC address from the database.

     mac:deny
             Set the ACL policy to deny association only by stations
             registered in the database.

     mac:kick address
             Force the specified station to be deauthenticated.  This
             typically is done to block a station after updating the address
             database.

     mac:open
             Set the ACL policy to allow all stations to associate.

     mac:flush
             Delete all entries in the database.

     The following parameters are for compatibility with other systems:

     nwid ssid
             Another name for the ssid parameter.  Included for NetBSD
             compatibility.

     station name
             Another name for the stationname parameter.  Included for BSD/OS
             compatibility.

     wep     Another way of saying wepmode on.  Included for BSD/OS
             compatibility.

     -wep    Another way of saying wepmode off.  Included for BSD/OS
             compatibility.

     nwkey key
             Another way of saying: ``wepmode on weptxkey 1 wepkey 1:key
             wepkey 2:- wepkey 3:- wepkey 4:-''.  Included for NetBSD
             compatibility.

     nwkey n:k1,k2,k3,k4
             Another way of saying ``wepmode on weptxkey n wepkey 1:k1 wepkey
             2:k2 wepkey 3:k3 wepkey 4:k4''.  Included for NetBSD
             compatibility.

     -nwkey  Another way of saying wepmode off.  Included for NetBSD
             compatibility.

     The following parameters are specific to bridge interfaces:

     addm interface
             Add the interface named by interface as a member of the bridge.
             The interface is put into promiscuous mode so that it can receive
             every packet sent on the network.

     deletem interface
             Remove the interface named by interface from the bridge.
             Promiscuous mode is disabled on the interface when it is removed
             from the bridge.

     maxaddr size
             Set the size of the bridge address cache to size.  The default is
             100 entries.

     timeout seconds
             Set the timeout of address cache entries to seconds seconds.  If
             seconds is zero, then address cache entries will not be expired.
             The default is 240 seconds.

     addr    Display the addresses that have been learned by the bridge.

     static interface-name address
             Add a static entry into the address cache pointing to
             interface-name.  Static entries are never aged out of the cache
             or re-placed, even if the address is seen on a different
             interface.

     deladdr address
             Delete address from the address cache.

     flush   Delete all dynamically-learned addresses from the address cache.

     flushall
             Delete all addresses, including static addresses, from the
             address cache.

     discover interface
             Mark an interface as a ``discovering'' interface.  When the
             bridge has no address cache entry (either dynamic or static) for
             the destination address of a packet, the bridge will forward the
             packet to all member interfaces marked as ``discovering''.  This
             is the default for all interfaces added to a bridge.

     -discover interface
             Clear the ``discovering'' attribute on a member interface.  For
             packets without the ``discovering'' attribute, the only packets
             forwarded on the interface are broadcast or multicast packets and
             packets for which the destination address is known to be on the
             interface's segment.

     learn interface
             Mark an interface as a ``learning'' interface.  When a packet
             arrives on such an interface, the source address of the packet is
             entered into the address cache as being a destination address on
             the interface's segment.  This is the default for all interfaces
             added to a bridge.

     -learn interface
             Clear the ``learning'' attribute on a member interface.

     sticky interface
             Mark an interface as a ``sticky'' interface.  Dynamically learned
             address entries are treated at static once entered into the
             cache.  Sticky entries are never aged out of the cache or
             replaced, even if the address is seen on a different interface.

     -sticky interface
             Clear the ``sticky'' attribute on a member interface.

     private interface
             Mark an interface as a ``private'' interface.  A private
             interface does not forward any traffic to any other port that is
             also a private interface.

     -private interface
             Clear the ``private'' attribute on a member interface.

     span interface
             Add the interface named by interface as a span port on the
             bridge.  Span ports transmit a copy of every frame received by
             the bridge.  This is most useful for snooping a bridged network
             passively on another host connected to one of the span ports of
             the bridge.

     -span interface
             Delete the interface named by interface from the list of span
             ports of the bridge.

     stp interface
             Enable Spanning Tree protocol on interface.  The if_bridge(4)
             driver has support for the IEEE 802.1D Spanning Tree protocol
             (STP).  Spanning Tree is used to detect and remove loops in a
             network topology.

     -stp interface
             Disable Spanning Tree protocol on interface.  This is the default
             for all interfaces added to a bridge.

     edge interface
             Set interface as an edge port.  An edge port connects directly to
             end stations cannot create bridging loops in the network, this
             allows it to transition straight to forwarding.

     -edge interface
             Disable edge status on interface.

     autoedge interface
             Allow interface to automatically detect edge status.  This is the
             default for all interfaces added to a bridge.

     -autoedge interface
             Disable automatic edge status on interface.

     ptp interface
             Set the interface as a point to point link.  This is required for
             straight transitions to forwarding and should be enabled on a
             direct link to another RSTP capable switch.

     -ptp interface
             Disable point to point link status on interface.  This should be
             disabled for a half duplex link and for an interface connected to
             a shared network segment, like a hub or a wireless network.

     autoptp interface
             Automatically detect the point to point status on interface by
             checking the full duplex link status.  This is the default for
             interfaces added to the bridge.

     -autoptp interface
             Disable automatic point to point link detection on interface.

     maxage seconds
             Set the time that a Spanning Tree protocol configuration is
             valid.  The default is 20 seconds.  The minimum is 6 seconds and
             the maximum is 40 seconds.

     fwddelay seconds
             Set the time that must pass before an interface begins forwarding
             packets when Spanning Tree is enabled.  The default is 15
             seconds.  The minimum is 4 seconds and the maximum is 30 seconds.

     hellotime seconds
             Set the time between broadcasting of Spanning Tree protocol
             configuration messages.  The hello time may only be changed when
             operating in legacy stp mode.  The default is 2 seconds.  The
             minimum is 1 second and the maximum is 2 seconds.

     priority value
             Set the bridge priority for Spanning Tree.  The default is 32768.
             The minimum is 0 and the maximum is 61440.

     proto value
             Set the Spanning Tree protocol.  The default is rstp.  The
             available options are stp and rstp.

     holdcnt value
             Set the transmit hold count for Spanning Tree.  This is the
             number of packets transmitted before being rate limited.  The
             default is 6.  The minimum is 1 and the maximum is 10.

     ifpriority interface value
             Set the Spanning Tree priority of interface to value.  The
             default is 128.  The minimum is 0 and the maximum is 240.

     ifpathcost interface value
             Set the Spanning Tree path cost of interface to value.  The
             default is calculated from the link speed.  To change a
             previously selected path cost back to automatic, set the cost to
             0.  The minimum is 1 and the maximum is 200000000.

     The following parameters are specific to lagg interfaces:

     laggport interface
             Add the interface named by interface as a port of the aggregation
             interface.

     -laggport interface
             Remove the interface named by interface from the aggregation
             interface.

     laggproto proto
             Set the aggregation protocol.  The default is failover.  The
             available options are failover, fec, lacp, loadbalance,
             roundrobin and none.

     The following parameters are specific to IP tunnel interfaces, gif(4):

     tunnel src_addr dest_addr
             Configure the physical source and destination address for IP
             tunnel interfaces.  The arguments src_addr and dest_addr are
             interpreted as the outer source/destination for the encapsulating
             IPv4/IPv6 header.

     -tunnel
             Unconfigure the physical source and destination address for IP
             tunnel interfaces previously configured with tunnel.

     deletetunnel
             Another name for the -tunnel parameter.

     The following parameters are specific to pfsync(4) interfaces:

     maxupd n
             Set the maximum number of updates for a single state which can be
             collapsed into one.  This is an 8-bit number; the default value
             is 128.

     The following parameters are specific to vlan(4) interfaces:

     vlan vlan_tag
             Set the VLAN tag value to vlan_tag.  This value is a 16-bit
             number which is used to create an 802.1Q VLAN header for packets
             sent from the vlan(4) interface.  Note that vlan and vlandev must
             both be set at the same time.

     vlandev iface
             Associate the physical interface iface with a vlan(4) interface.
             Packets transmitted through the vlan(4) interface will be
             diverted to the specified physical interface iface with 802.1Q
             VLAN encapsulation.  Packets with 802.1Q encapsulation received
             by the parent interface with the correct VLAN tag will be
             diverted to the associated vlan(4) pseudo-interface.  The vlan(4)
             interface is assigned a copy of the parent interface's flags and
             the parent's ethernet address.  The vlandev and vlan must both be
             set at the same time.  If the vlan(4) interface already has a
             physical interface associated with it, this command will fail.
             To change the association to another physical interface, the
             existing association must be cleared first.

             Note: if the hardware tagging capability is set on the parent
             interface, the vlan(4) pseudo interface's behavior changes: the
             vlan(4) interface recognizes that the parent interface supports
             insertion and extraction of VLAN tags on its own (usually in
             firmware) and that it should pass packets to and from the parent
             unaltered.

     -vlandev [iface]
             If the driver is a vlan(4) pseudo device, disassociate the parent
             interface from it.  This breaks the link between the vlan(4)
             interface and its parent, clears its VLAN tag, flags and its link
             address and shuts the interface down.  The iface argument is
             useless and hence deprecated.

     The following parameters are specific to carp(4) interfaces:

     advbase seconds
             Specifies the base of the advertisement interval in seconds.  The
             acceptable values are 1 to 255.  The default value is 1.

     advskew interval
             Specifies the skew to add to the base advertisement interval to
             make one host advertise slower than another host.  It is
             specified in 1/256 of seconds.  The acceptable values are 1 to
             254.  The default value is 0.

     pass phrase
             Set the authentication key to phrase.

     vhid n  Set the virtual host ID.  This is a required setting.  Acceptable
             values are 1 to 255.

     The ifconfig utility displays the current configuration for a network
     interface when no optional parameters are supplied.  If a protocol family
     is specified, ifconfig will report only the details specific to that
     protocol family.

     If the -m flag is passed before an interface name, ifconfig will display
     the capability list and all of the supported media for the specified
     interface.  If -L flag is supplied, address lifetime is displayed for
     IPv6 addresses, as time offset string.

     Optionally, the -a flag may be used instead of an interface name.  This
     flag instructs ifconfig to display information about all interfaces in
     the system.  The -d flag limits this to interfaces that are down, and -u
     limits this to interfaces that are up.  When no arguments are given, -a
     is implied.

     The -l flag may be used to list all available interfaces on the system,
     with no other additional information.  Use of this flag is mutually
     exclusive with all other flags and commands, except for -d (only list
     interfaces that are down) and -u (only list interfaces that are up).

     The -v flag may be used to get more verbose status for an interface.

     The -C flag may be used to list all of the interface cloners available on
     the system, with no additional information.  Use of this flag is mutually
     exclusive with all other flags and commands.

     The -k flag causes keying information for the interface, if available, to
     be printed.  For example, the values of 802.11 WEP keys will be printed,
     if accessible to the current user.  This information is not printed by
     default, as it may be considered sensitive.

     If the network interface driver is not present in the kernel then
     ifconfig will attempt to load it.  The -n flag disables this behavior.

     Only the super-user may modify the configuration of a network interface.

NOTES
     The media selection system is relatively new and only some drivers
     support it (or have need for it).

EXAMPLES
     Assign the IPv4 address 192.0.2.10, with a network mask of 255.255.255.0,
     to the interface fxp0:
           # ifconfig fxp0 inet 192.0.2.10 netmask 255.255.255.0

     Add the IPv4 address 192.0.2.45, with the CIDR network prefix /28, to the
     interface ed0, using add as a synonym for the canonical form of the
     option alias:
           # ifconfig ed0 inet 192.0.2.45/28 add

     Remove the IPv4 address 192.0.2.45 from the interface ed0:
           # ifconfig ed0 inet 192.0.2.45 -alias

     Add the IPv6 address 2001:DB8:DBDB::123/48 to the interface em0:
           # ifconfig em0 inet6 2001:db8:bdbd::123 prefixlen 48 alias
     Note that lower case hexadecimal IPv6 addresses are acceptable.

     Remove the IPv6 address added in the above example, using the / character
     as shorthand for the network prefix, and using delete as a synonym for
     the canonical form of the option -alias:
           # ifconfig em0 inet6 2001:db8:bdbd::123/48 delete

     Configure the interface xl0, to use 100baseTX, full duplex Ethernet media
     options:
           # ifconfig xl0 media 100baseTX mediaopt full-duplex

     Create the software network interface gif1:
           # ifconfig gif1 create

     Destroy the software network interface gif1:
           # ifconfig gif1 destroy

DIAGNOSTICS
     Messages indicating the specified interface does not exist, the requested
     address is unknown, or the user is not privileged and tried to alter an
     interface's configuration.

SEE ALSO
     netstat(1), carp(4), netintro(4), pfsync(4), polling(4), vlan(4), rc(8),
     routed(8), sysctl(8)

HISTORY
     The ifconfig utility appeared in 4.2BSD.

BUGS
     Basic IPv6 node operation requires a link-local address on each interface
     configured for IPv6.  Normally, such an address is automatically
     configured by the kernel on each interface added to the system; this
     behaviour may be disabled by setting the sysctl MIB variable
     net.inet6.ip6.auto_linklocal to 0.

     If you delete such an address using ifconfig, the kernel may act very
     odd.  Do this at your own risk.

FreeBSD 11.0-PRERELEASE        October 31, 2007        FreeBSD 11.0-PRERELEASE

NAME | SYNOPSIS | DESCRIPTION | NOTES | EXAMPLES | DIAGNOSTICS | SEE ALSO | HISTORY | BUGS

Want to link to this manual page? Use this URL:
<https://www.freebsd.org/cgi/man.cgi?query=ifconfig&sektion=8&manpath=FreeBSD+7.0-RELEASE>

home | help