Provided by: wpasupplicant_0.7.3-6ubuntu2_i386 bug


       wpa_supplicant   -  Wi-Fi  Protected  Access  client  and  IEEE  802.1X


       wpa_supplicant [ -BddfhKLqqtuvW ] [ -iifname ]  [  -cconfig  file  ]  [
       -Ddriver ] [ -PPID_file ] [ -foutput file ]


       Wireless  networks  do  not  require  physical  access  to  the network
       equipment in the same way as wired networks. This makes it  easier  for
       unauthorized  users  to  passively  monitor  a  network and capture all
       transmitted frames.  In addition, unauthorized use of  the  network  is
       much  easier.  In  many  cases,  this  can  happen  even without user's
       explicit knowledge  since  the  wireless  LAN  adapter  may  have  been
       configured to automatically join any available network.

       Link-layer  encryption  can  be used to provide a layer of security for
       wireless networks. The original wireless  LAN  standard,  IEEE  802.11,
       included a simple encryption mechanism, WEP. However, that proved to be
       flawed in many areas and network protected with WEP cannot be  consider
       secure.  IEEE  802.1X authentication and frequently changed dynamic WEP
       keys can be used to improve the network security,  but  even  that  has
       inherited  security  issues due to the use of WEP for encryption. Wi-Fi
       Protected Access  and  IEEE  802.11i  amendment  to  the  wireless  LAN
       standard  introduce  a much improvement mechanism for securing wireless
       networks. IEEE 802.11i enabled networks that are using CCMP (encryption
       mechanism  based  on strong cryptographic algorithm AES) can finally be
       called secure used for applications which require efficient  protection
       against unauthorized access.

       wpa_supplicant  is  an  implementation of the WPA Supplicant component,
       i.e., the part that runs in the client stations. It implements WPA  key
       negotiation  with  a  WPA  Authenticator  and  EAP  authentication with
       Authentication Server. In addition, it controls the  roaming  and  IEEE
       802.11 authentication/association of the wireless LAN driver.

       wpa_supplicant  is  designed  to be a "daemon" program that runs in the
       background and acts as the backend component controlling  the  wireless
       connection.  wpa_supplicant  supports separate frontend programs and an
       example text-based frontend, wpa_cli, is included with wpa_supplicant.

       Before wpa_supplicant can do its work, the network  interface  must  be
       available.   That  means  that  the physical device must be present and
       enabled, and the driver for the device must be loaded. The daemon  will
       exit immediately if the device is not already available.

       After  wpa_supplicant  has  configured the network device, higher level
       configuration such as DHCP may proceed.  There are a variety of ways to
       integrate  wpa_supplicant into a machine's networking scripts, a few of
       which are described in sections below.

       The following steps are used when associating with an AP using WPA:

       · wpa_supplicant requests the kernel driver to scan neighboring BSSes

       · wpa_supplicant selects a BSS based on its configuration

       · wpa_supplicant requests the  kernel  driver  to  associate  with  the
         chosen BSS

       · If   WPA-EAP:   integrated   IEEE  802.1X  Supplicant  completes  EAP
         authentication  with  the  authentication  server  (proxied  by   the
         Authenticator in the AP)

       · If WPA-EAP: master key is received from the IEEE 802.1X Supplicant

       · If WPA-PSK: wpa_supplicant uses PSK as the master session key

       · wpa_supplicant  completes WPA 4-Way Handshake and Group Key Handshake
         with the Authenticator (AP)

       · wpa_supplicant configures encryption keys for unicast and broadcast

       · normal data packets can be transmitted and received


       Supported WPA/IEEE 802.11i features:

       · WPA-PSK ("WPA-Personal")

       · WPA  with  EAP  (e.g.,  with  RADIUS  authentication  server)  ("WPA-
         Enterprise")  Following  authentication methods are supported with an
         integrate IEEE 802.1X Supplicant:

         · EAP-TLS

         · EAP-PEAP/MSCHAPv2 (both PEAPv0 and PEAPv1)

         · EAP-PEAP/TLS (both PEAPv0 and PEAPv1)

         · EAP-PEAP/GTC (both PEAPv0 and PEAPv1)

         · EAP-PEAP/OTP (both PEAPv0 and PEAPv1)

         · EAP-PEAP/MD5-Challenge (both PEAPv0 and PEAPv1)

         · EAP-TTLS/EAP-MD5-Challenge

         · EAP-TTLS/EAP-GTC

         · EAP-TTLS/EAP-OTP

         · EAP-TTLS/EAP-MSCHAPv2

         · EAP-TTLS/EAP-TLS

         · EAP-TTLS/MSCHAPv2

         · EAP-TTLS/MSCHAP

         · EAP-TTLS/PAP

         · EAP-TTLS/CHAP

         · EAP-SIM

         · EAP-AKA

         · EAP-PSK

         · EAP-PAX

         · LEAP (note: requires special  support  from  the  driver  for  IEEE
           802.11 authentication)

         · (following  methods  are  supported, but since they do not generate
           keying material, they cannot be used with WPA or  IEEE  802.1X  WEP

         · EAP-MD5-Challenge

         · EAP-MSCHAPv2

         · EAP-GTC

         · EAP-OTP

       · key management for CCMP, TKIP, WEP104, WEP40

       · RSN/WPA2 (IEEE 802.11i)

         · pre-authentication

         · PMKSA caching


       A  summary  of  available driver backends is below. Support for each of
       the driver backends is chosen at wpa_supplicant  compile  time.  For  a
       list  of  supported driver backends that may be used with the -D option
       on  your  system,  refer  to  the   help   output   of   wpa_supplicant
       (wpa_supplicant -h).

       hostap (default)  Host  AP  driver  (Intersil Prism2/2.5/3).  (this can
              also be used with Linuxant DriverLoader).

       hermes Agere Systems Inc. driver (Hermes-I/Hermes-II).

              MADWIFI 802.11 support (Atheros, etc.).

       atmel  ATMEL AT76C5XXx (USB, PCMCIA).

       wext   Linux wireless extensions (generic).

              Linux ndiswrapper.

              Broadcom wl.o driver.

       ipw    Intel ipw2100/2200 driver.

       wired  wpa_supplicant wired Ethernet driver

              wpa_supplicant Broadcom switch driver

       bsd    BSD 802.11 support (Atheros, etc.).

       ndis   Windows NDIS driver.


       Most command line  options  have  global  scope.  Some  are  given  per
       interface,  and  are only valid if at least one -i option is specified,
       otherwise they're ignored. Option groups for different interfaces  must
       be separated by -N option.

       -b br_ifname
              Optional bridge interface name. (Per interface)

       -B     Run daemon in the background.

       -c filename
              Path to configuration file. (Per interface)

       -C ctrl_interface
              Path to ctrl_interface socket (Per interface. Only used if -c is

       -i ifname
              Interface to listen on. Multiple instances of this option can be
              present, one per interface, separated by -N option (see below).

       -d     Increase debugging verbosity (-dd even more).

       -D driver
              Driver  to  use  (can  be multiple drivers: nl80211,wext).  (Per
              interface, see the available options below.)

       -f output file
              Log output to specified file instead of stdout.

       -g global ctrl_interface
              Path to global ctrl_interface socket.  If  specified,  interface
              definitions may be omitted.

       -K     Include keys (passwords, etc.) in debug output.

       -t     Include timestamp in debug messages.

       -h     Help.  Show a usage message.

       -L     Show license (GPL and BSD).

       -p     Driver parameters. (Per interface)

       -P PID_file
              Path to PID file.

       -q     Decrease debugging verbosity (-qq even less).

       -u     Enabled   DBus   control   interface.   If   enabled,  interface
              definitions may be omitted.

       -v     Show version.

       -W     Wait for a control interface monitor before starting.

       -N     Start describing new interface.


       In most common cases, wpa_supplicant is started with:

              wpa_supplicant -B -c/etc/wpa_supplicant.conf -iwlan0

       This makes the process fork into background.

       The easiest way to debug  problems,  and  to  get  debug  log  for  bug
       reports,  is  to  start  wpa_supplicant  on  foreground  with debugging

              wpa_supplicant -c/etc/wpa_supplicant.conf -iwlan0 -d

       If the specific driver wrapper is not known beforehand, it is  possible
       to  specify  multiple  comma  separated  driver wrappers on the command
       line. wpa_supplicant will use the first driver wrapper that is able  to
       initialize the interface.

              wpa_supplicant -Dnl80211,wext -c/etc/wpa_supplicant.conf -iwlan0

       wpa_supplicant  can  control  multiple  interfaces  (radios)  either by
       running one process for each interface separately or  by  running  just
       one  process  and  list  of  options at command line. Each interface is
       separated with -N argument. As  an  example,  following  command  would
       start wpa_supplicant for two interfaces:

              wpa_supplicant \
                   -c wpa1.conf -i wlan0 -D hostap -N \
                   -c wpa2.conf -i ath0 -D madwifi


       Current hardware/software requirements:

       · Linux  kernel  2.4.x  or  2.6.x with Linux Wireless Extensions v15 or

       · FreeBSD 6-CURRENT

       · Microsoft Windows with WinPcap (at least WinXP, may work  with  other


       Host AP driver for Prism2/2.5/3 (development snapshot/v0.2.x)
              (  Driver  needs  to be set in Managed
              mode (iwconfig wlan0 mode managed).  Please  note  that  station
              firmware version needs to be 1.7.0 or newer to work in WPA mode.

       Linuxant DriverLoader
              ( with Windows NDIS driver
              for your wlan card supporting WPA.

       Agere Systems Inc. Linux Driver
              (  Please  note  that  the
              driver  interface  file  (driver_hermes.c) and hardware specific
              include  files  are   not   included   in   the   wpa_supplicant
              distribution.  You  will  need  to  copy  these  from the source
              package of the Agere driver.

       madwifi driver for cards based on Atheros chip set (ar521x)
              ( Please note that  you
              will  need  to modify the wpa_supplicant .config file to use the
              correct path for the madwifi driver root  directory  (CFLAGS  +=
              -I../madwifi/wpa line in example defconfig).

       ATMEL AT76C5XXx driver for USB and PCMCIA cards

       Linux ndiswrapper
              ( with Windows NDIS driver.

       Broadcom wl.o driver
              This  is  a  generic  Linux  driver  for Broadcom IEEE 802.11a/g
              cards.  However, it is proprietary driver that is  not  publicly
              available except for couple of exceptions, mainly Broadcom-based
              APs/wireless routers that use Linux. The driver  binary  can  be
              downloaded,      e.g.,     from     Linksys     support     site
              ( for Linksys WRT54G. The
              GPL  tarball includes cross-compiler and the needed header file,
              wlioctl.h, for compiling wpa_supplicant.  This driver support in
              wpa_supplicant is expected to work also with other devices based
              on Broadcom driver (assuming the  driver  includes  client  mode

        Intel ipw2100 driver

       Intel ipw2200 driver

       Linux wireless extensions
              In  theory,  any  driver that supports Linux wireless extensions
              can be  used  with  IEEE  802.1X  (i.e.,  not  WPA)  when  using
              ap_scan=0 option in configuration file.

       Wired Ethernet drivers
              Use ap_scan=0.

       BSD net80211 layer (e.g., Atheros driver)
              At the moment, this is for FreeBSD 6-CURRENT branch.

       Windows NDIS
              The      current      Windows      port     requires     WinPcap
              (  See  README-Windows.txt  for  more

       wpa_supplicant  was  designed  to be portable for different drivers and
       operating systems. Hopefully, support for more wlan cards and OSes will
       be  added  in  the future. See developer.txt for more information about
       the design of wpa_supplicant and porting to  other  drivers.  One  main
       goal  is  to  add full WPA/WPA2 support to Linux wireless extensions to
       allow new drivers to be  supported  without  having  to  implement  new
       driver-specific interface code in wpa_supplicant.


       The wpa_supplicant system consists of the following components:

              the  configuration  file  describing  all networks that the user
              wants the computer to connect to.

              the program that directly interacts with the network interface.

              the client program that provides a high-level interface  to  the
              functionality of the daemon.

              a  utility  needed  to  construct wpa_supplicant.conf files that
              include encrypted passwords.


       First, make a configuration file, e.g.  /etc/wpa_supplicant.conf,  that
       describes    the    networks    you    are    interested    in.     See
       wpa_supplicant.conf(5) for details.

       Once the configuration is ready, you can test whether the configuration
       works  by  running wpa_supplicant with following command to start it on
       foreground with debugging enabled:

              wpa_supplicant -iwlan0 -c/etc/wpa_supplicant.conf -d

       Assuming everything goes fine, you can start using following command to
       start wpa_supplicant on background without debugging:

              wpa_supplicant -iwlan0 -c/etc/wpa_supplicant.conf -B

       Please  note that if you included more than one driver interface in the
       build time configuration (.config),  you  may  need  to  specify  which
       interface  to  use  by  including -D<driver name> option on the command


       For example, following small changes to pcmcia-cs scripts can  be  used
       to enable WPA support:

       Add   MODE="Managed"   and   WPA="y"   to   the   network   scheme   in

       Add the  following  block  to  the  end  of  start  action  handler  in

              if [ "$WPA" = "y" -a -x /usr/local/bin/wpa_supplicant ]; then
                  /usr/local/bin/wpa_supplicant -B -c/etc/wpa_supplicant.conf -i$DEVICE

       Add  the following block to the end of stop action handler (may need to
       be separated from other actions) in /etc/pcmcia/wireless:

              if [ "$WPA" = "y" -a -x /usr/local/bin/wpa_supplicant ]; then
                  killall wpa_supplicant

       This will make cardmgr start wpa_supplicant when the  card  is  plugged


       wpa_background(8) wpa_supplicant.conf(5) wpa_cli(8) wpa_passphrase(8)


       wpa_supplicant  is copyright (c) 2003-2007, Jouni Malinen <> and
       contributors.  All Rights Reserved.

       This program is dual-licensed under both the  GPL  version  2  and  BSD
       license. Either license may be used at your option.

                               07 September 2010             WPA_SUPPLICANT(8)