Provided by: wireless-tools_30~pre9-16.1ubuntu2_amd64 bug

NAME

       iwconfig - configure a wireless network interface

SYNOPSIS

       iwconfig [interface]
       iwconfig interface [essid X] [nwid N] [mode M] [freq F]
                          [channel C][sens S ][ap A ][nick NN ]
                          [rate R] [rts RT] [frag FT] [txpower T]
                          [enc E] [key K] [power P] [retry R]
                          [modu M] [commit]
       iwconfig --help
       iwconfig --version

DESCRIPTION

       Iwconfig  is  similar  to ifconfig(8), but is dedicated to the wireless interfaces. It is used to set the
       parameters of the network interface which are specific to the  wireless  operation  (for  example  :  the
       frequency).   Iwconfig  may  also  be  used  to  display  those  parameters,  and the wireless statistics
       (extracted from /proc/net/wireless).

       All these parameters and statistics are device dependent. Each driver will  provide  only  some  of  them
       depending  on  hardware support, and the range of values may change. Please refer to the man page of each
       device for details.

PARAMETERS

       essid  Set the ESSID (or Network Name - in some products it may also be called Domain ID). The  ESSID  is
              used to identify cells which are part of the same virtual network.
              As  opposed  to  the  AP  Address or NWID which define a single cell, the ESSID defines a group of
              cells connected via repeaters or infrastructure, where the user may roam transparently.
              With some cards, you may disable the ESSID checking (ESSID promiscuous) with off or any (and on to
              reenable it).
              If the ESSID of your network is one of the special keywords (off, on or any), you should use -- to
              escape it.
              Examples :
                   iwconfig eth0 essid any
                   iwconfig eth0 essid "My Network"
                   iwconfig eth0 essid -- "ANY"

       nwid   Set the Network ID. As all adjacent wireless networks share the same  medium,  this  parameter  is
              used to differentiate them (create logical colocated networks) and identify nodes belonging to the
              same cell.
              This parameter is only used for pre-802.11 hardware, the 802.11 protocol uses  the  ESSID  and  AP
              Address for this function.
              With  some  cards,  you may disable the Network ID checking (NWID promiscuous) with off (and on to
              reenable it).
              Examples :
                   iwconfig eth0 nwid AB34
                   iwconfig eth0 nwid off

       nick[name]
              Set the nickname, or the station name. Some 802.11 products do define it, but this is not used  as
              far  as  the protocols (MAC, IP, TCP) are concerned and completely useless as far as configuration
              goes. Only some wireless diagnostic tools may use it.
              Example :
                   iwconfig eth0 nickname "My Linux Node"

       mode   Set the operating mode of the device, which depends on the network topology. The mode can  be  Ad-
              Hoc  (network  composed  of  only  one cell and without Access Point), Managed (node connects to a
              network composed of many Access Points, with roaming), Master (the  node  is  the  synchronisation
              master  or  acts  as  an Access Point), Repeater (the node forwards packets between other wireless
              nodes), Secondary (the node acts as a backup master/repeater), Monitor (the node is not associated
              with any cell and passively monitor all packets on the frequency) or Auto.
              Example :
                   iwconfig eth0 mode Managed
                   iwconfig eth0 mode Ad-Hoc

       freq/channel
              Set  the  operating  frequency  or  channel  in the device. A value below 1000 indicates a channel
              number, a value greater than 1000 is a frequency in Hz. You may append the suffix k, M or G to the
              value (for example, "2.46G" for 2.46 GHz frequency), or add enough '0'.
              Channels  are usually numbered starting at 1, and you may use iwlist(8) to get the total number of
              channels, list the available  frequencies,  and  display  the  current  frequency  as  a  channel.
              Depending on regulations, some frequencies/channels may not be available.
              When  using  Managed  mode,  most  often  the Access Point dictates the channel and the driver may
              refuse the setting of the frequency. In Ad-Hoc mode, the frequency setting may  only  be  used  at
              initial cell creation, and may be ignored when joining an existing cell.
              You may also use off or auto to let the card pick up the best channel (when supported).
              Examples :
                   iwconfig eth0 freq 2422000000
                   iwconfig eth0 freq 2.422G
                   iwconfig eth0 channel 3
                   iwconfig eth0 channel auto

       ap     Force  the  card  to  register  to  the Access Point given by the address, if it is possible. This
              address is the cell identity of the Access Point, as reported by wireless scanning, which  may  be
              different from its network MAC address. If the wireless link is point to point, set the address of
              the other end of the link. If the link is ad-hoc, set the cell identity of the ad-hoc network.
              When the quality of the connection goes too low, the driver may revert back to automatic mode (the
              card selects the best Access Point in range).
              You may also use off to re-enable automatic mode without changing the current Access Point, or you
              may use any or auto to force the card to reassociate with the currently best Access Point.
              Example :
                   iwconfig eth0 ap 00:60:1D:01:23:45
                   iwconfig eth0 ap any
                   iwconfig eth0 ap off

       rate/bit[rate]
              For cards supporting multiple bit rates, set the bit-rate in b/s. The bit-rate  is  the  speed  at
              which  bits  are  transmitted  over  the medium, the user speed of the link is lower due to medium
              sharing and various overhead.
              You may append the suffix k, M or G to the value (decimal multiplier : 10^3, 10^6 and  10^9  b/s),
              or add enough '0'. Values below 1000 are card specific, usually an index in the bit-rate list. Use
              auto to select automatic bit-rate mode (fallback to lower rate on noisy channels),  which  is  the
              default for most cards, and fixed to revert back to fixed setting. If you specify a bit-rate value
              and append auto, the driver will use all bit-rates lower and equal than this value.
              Examples :
                   iwconfig eth0 rate 11M
                   iwconfig eth0 rate auto
                   iwconfig eth0 rate 5.5M auto

       txpower
              For cards supporting multiple transmit powers, sets the transmit power in dBm. If W is  the  power
              in  Watt,  the  power  in  dBm is P = 30 + 10.log(W).  If the value is postfixed by mW, it will be
              automatically converted to dBm.
              In addition, on and off enable and disable the radio, and auto and fixed enable and disable  power
              control (if those features are available).
              Examples :
                   iwconfig eth0 txpower 15
                   iwconfig eth0 txpower 30mW
                   iwconfig eth0 txpower auto
                   iwconfig eth0 txpower off

       sens   Set  the sensitivity threshold. This define how sensitive is the card to poor operating conditions
              (low signal, interference). Positive values are assumed to be the raw value used by  the  hardware
              or  a percentage, negative values are assumed to be dBm. Depending on the hardware implementation,
              this parameter may control various functions.
              On modern cards, this parameter usually control  handover/roaming  threshold,  the  lowest  signal
              level  for  which  the  hardware remains associated with the current Access Point. When the signal
              level goes below this threshold the card starts looking for a new/better Access Point. Some  cards
              may  use the number of missed beacons to trigger this. For high density of Access Points, a higher
              threshold make sure the card is always associated with the best AP, for  low  density  of  APs,  a
              lower threshold minimise the number of failed handoffs.
              On  more ancient card this parameter usually controls the defer threshold, the lowest signal level
              for which the hardware considers the channel busy. Signal levels above  this  threshold  make  the
              hardware  inhibits  its  own  transmission  whereas  signals  weaker than this are ignored and the
              hardware is free to transmit. This is usually strongly linked to the receive threshold, the lowest
              signal  level for which the hardware attempts packet reception. Proper setting of these thresholds
              prevent the card to waste time on background  noise  while  still  receiving  weak  transmissions.
              Modern designs seems to control those thresholds automatically.
              Example :
                   iwconfig eth0 sens -80
                   iwconfig eth0 sens 2

       retry  Most cards have MAC retransmissions, and some allow to set the behaviour of the retry mechanism.
              To  set  the  maximum  number of retries, enter limit `value'.  This is an absolute value (without
              unit), and the default (when nothing is specified).  To set the maximum length  of  time  the  MAC
              should  retry, enter lifetime `value'.  By defaults, this value is in seconds, append the suffix m
              or u to specify values in milliseconds or microseconds.
              You can also add the short, long, min and max modifiers. If the card supports automatic mode, they
              define  the bounds of the limit or lifetime. Some other cards define different values depending on
              packet size, for example in 802.11 min limit is the short retry limit (non RTS/CTS packets).
              Examples :
                   iwconfig eth0 retry 16
                   iwconfig eth0 retry lifetime 300m
                   iwconfig eth0 retry short 12
                   iwconfig eth0 retry min limit 8

       rts[_threshold]
              RTS/CTS adds a handshake before each packet transmission to make sure that the channel  is  clear.
              This  adds overhead, but increases performance in case of hidden nodes or a large number of active
              nodes. This parameter sets the size of the smallest packet for which the node sends RTS ; a  value
              equal  to the maximum packet size disables the mechanism. You may also set this parameter to auto,
              fixed or off.
              Examples :
                   iwconfig eth0 rts 250
                   iwconfig eth0 rts off

       frag[mentation_threshold]
              Fragmentation allows to split an IP packet in a burst of  smaller  fragments  transmitted  on  the
              medium.  In  most cases this adds overhead, but in a very noisy environment this reduces the error
              penalty and allow packets to get through interference bursts.  This  parameter  sets  the  maximum
              fragment size which is always lower than the maximum packet size.
              This  parameter  may  also  control  Frame  Bursting  available on some cards, the ability to send
              multiple IP packets together. This mechanism would be enabled if the fragment size is larger  than
              the maximum packet size.
              You may also set this parameter to auto, fixed or off.
              Examples :
                   iwconfig eth0 frag 512
                   iwconfig eth0 frag off

       key/enc[ryption]
              Used to manipulate encryption or scrambling keys and security mode.
              To  set  the  current  encryption  key, just enter the key in hex digits as XXXX-XXXX-XXXX-XXXX or
              XXXXXXXX.  To set a key other than the current key, prepend or append [index] to  the  key  itself
              (this  won't  change  which  is  the active key). You can also enter the key as an ASCII string by
              using the s: prefix. Passphrase is currently not supported.
              To change which key is the currently active key, just enter  [index]  (without  entering  any  key
              value).
              off and on disable and reenable encryption.
              The  security  mode may be open or restricted, and its meaning depends on the card used. With most
              cards, in open mode no authentication is used and the card may also accept non-encrypted sessions,
              whereas  in  restricted  mode  only  encrypted  sessions  are  accepted  and  the  card  will  use
              authentication if available.
              If you need to set multiple keys, or set a key and change the active key, you need to use multiple
              key directives. Arguments can be put in any order, the last one will take precedence.
              Examples :
                   iwconfig eth0 key 0123-4567-89
                   iwconfig eth0 key [3] 0123-4567-89
                   iwconfig eth0 key s:password [2]
                   iwconfig eth0 key [2]
                   iwconfig eth0 key open
                   iwconfig eth0 key off
                   iwconfig eth0 key restricted [3] 0123456789
                   iwconfig eth0 key 01-23 key 45-67 [4] key [4]

       power  Used to manipulate power management scheme parameters and mode.
              To set the period between wake ups, enter period `value'.  To set the timeout before going back to
              sleep, enter timeout `value'.  To set the generic level of power  saving,  enter  saving  `value'.
              You  can  also  add the min and max modifiers. By default, those values are in seconds, append the
              suffix m or u to specify values in milliseconds  or  microseconds.  Sometimes,  those  values  are
              without units (number of beacon periods, dwell, percentage or similar).
              off  and  on disable and reenable power management. Finally, you may set the power management mode
              to all (receive all packets),  unicast  (receive  unicast  packets  only,  discard  multicast  and
              broadcast) and multicast (receive multicast and broadcast only, discard unicast packets).
              Examples :
                   iwconfig eth0 power period 2
                   iwconfig eth0 power 500m unicast
                   iwconfig eth0 power timeout 300u all
                   iwconfig eth0 power saving 3
                   iwconfig eth0 power off
                   iwconfig eth0 power min period 2 power max period 4

       modu[lation]
              Force  the  card  to  use a specific set of modulations. Modern cards support various modulations,
              some which are standard, such as 802.11b or 802.11g, and some proprietary. This command force  the
              card  to  only use the specific set of modulations listed on the command line. This can be used to
              fix interoperability issues.
              The list of available modulations depend on the card/driver and  can  be  displayed  using  iwlist
              modulation.   Note  that  some  card/driver  may  not  be  able  to  select each modulation listed
              independently, some may come as a group.  You  may  also  set  this  parameter  to  auto  let  the
              card/driver do its best.
              Examples :
                   iwconfig eth0 modu 11g
                   iwconfig eth0 modu CCK OFDMa
                   iwconfig eth0 modu auto

       commit Some  cards  may  not apply changes done through Wireless Extensions immediately (they may wait to
              aggregate the changes or apply it only when the card is brought up via  ifconfig).   This  command
              (when available) forces the card to apply all pending changes.
              This is normally not needed, because the card will eventually apply the changes, but can be useful
              for debugging.

DISPLAY

       For each device which supports wireless extensions, iwconfig will display the name of  the  MAC  protocol
       used  (name  of  device for proprietary protocols), the ESSID (Network Name), the NWID, the frequency (or
       channel), the sensitivity, the mode of operation,  the  Access  Point  address,  the  bit-rate,  the  RTS
       threshold,  the  fragmentation threshold, the encryption key and the power management settings (depending
       on availability).

       The parameters displayed have the same meaning and values as the parameters you can set, please refer  to
       the previous part for a detailed explanation of them.
       Some  parameters are only displayed in short/abbreviated form (such as encryption). You may use iwlist(8)
       to get all the details.
       Some parameters have two modes (such as bitrate). If the value is prefixed by  `=',  it  means  that  the
       parameter is fixed and forced to that value, if it is prefixed by `:', the parameter is in automatic mode
       and the current value is shown (and may change).

       Access Point/Cell
              An address equal to 00:00:00:00:00:00 means that the card failed to associate with an Access Point
              (most  likely  a  configuration issue). The Access Point parameter will be shown as Cell in ad-hoc
              mode (for obvious reasons), but otherwise works the same.

       If /proc/net/wireless exists, iwconfig will also display its content. Note that those values will  depend
       on  the  driver  and the hardware specifics, so you need to refer to your driver documentation for proper
       interpretation of those values.

       Link quality
              Overall quality of the link. May be based on the level of contention or interference, the  bit  or
              frame  error rate, how good the received signal is, some timing synchronisation, or other hardware
              metric. This is an aggregate value, and depends totally on the driver and hardware.

       Signal level
              Received signal strength (RSSI - how strong the received signal is). May  be  arbitrary  units  or
              dBm,  iwconfig uses driver meta information to interpret the raw value given by /proc/net/wireless
              and display the proper unit or maximum value (using 8 bit arithmetic). In Ad-Hoc mode, this may be
              undefined and you should use iwspy.

       Noise level
              Background noise level (when no packet is transmitted). Similar comments as for Signal level.

       Rx invalid nwid
              Number  of  packets received with a different NWID or ESSID. Used to detect configuration problems
              or adjacent network existence (on the same frequency).

       Rx invalid crypt
              Number of packets that the hardware was unable to decrypt. This can  be  used  to  detect  invalid
              encryption settings.

       Rx invalid frag
              Number  of  packets  for  which  the  hardware was not able to properly re-assemble the link layer
              fragments (most likely one was missing).

       Tx excessive retries
              Number of packets that the hardware failed to deliver. Most MAC protocols will retry the packet  a
              number of times before giving up.

       Invalid misc
              Other packets lost in relation with specific wireless operations.

       Missed beacon
              Number  of  periodic beacons from the Cell or the Access Point we have missed. Beacons are sent at
              regular intervals to maintain the cell coordination, failure to  receive  them  usually  indicates
              that the card is out of range.

AUTHOR

       Jean Tourrilhes - jt@hpl.hp.com

FILES

       /proc/net/wireless

SEE ALSO

       ifconfig(8), iwspy(8), iwlist(8), iwevent(8), iwpriv(8), wireless(7).