Provided by: wpasupplicant_2.1-0ubuntu1.7+esm5_amd64 
NAME
wpa_supplicant - Wi-Fi Protected Access client and IEEE 802.1X supplicant
SYNOPSIS
wpa_supplicant [ -BddfhKLqqsTtuvW ] [ -iifname ] [ -cconfig file ] [ -Ddriver ] [
-PPID_file ] [ -foutput file ]
OVERVIEW
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 FEATURES
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 keying)
• 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
AVAILABLE DRIVERS
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).
wext Linux wireless extensions (generic).
wired wpa_supplicant wired Ethernet driver
roboswitch
wpa_supplicant Broadcom switch driver
bsd BSD 802.11 support (Atheros, etc.).
ndis Windows NDIS driver.
COMMAND LINE OPTIONS
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 not).
-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.)
-e entropy file
File for wpa_supplicant to use to maintain its internal entropy store in over
restarts.
-f output file
Log output to specified file instead of stdout. (This is only available if
wpa_supplicant was built with the CONFIG_DEBUG_FILE option.)
-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 (BSD).
-o override driver
Override the driver parameter for new interfaces.
-O override ctrl_interface
Override the ctrl_interface parameter for new interfaces.
-p Driver parameters. (Per interface)
-P PID_file
Path to PID file.
-q Decrease debugging verbosity (-qq even less).
-s Log output to syslog instead of stdout. (This is only available if wpa_supplicant
was built with the CONFIG_DEBUG_SYSLOG option.)
-T Log output to Linux tracing in addition to any other destinations. (This is only
available if wpa_supplicant was built with the CONFIG_DEBUG_LINUX_TRACING option.)
-t Include timestamp in debug messages.
-u Enable DBus control interface. If enabled, interface definitions may be omitted.
(This is only available if wpa_supplicant was built with the CONFIG_DBUS option.)
0
-v Show version.
-W Wait for a control interface monitor before starting.
-N Start describing new interface.
EXAMPLES
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 enabled:
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 nl80211 -N \
-c wpa2.conf -i ath0 -D wext
OS REQUIREMENTS
Current hardware/software requirements:
• Linux kernel 2.4.x or 2.6.x with Linux Wireless Extensions v15 or newer
• FreeBSD 6-CURRENT
• Microsoft Windows with WinPcap (at least WinXP, may work with other versions)
SUPPORTED DRIVERS
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 (http://winpcap.polito.it/). See README-
Windows.txt for more information.
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.
ARCHITECTURE
The wpa_supplicant system consists of the following components:
wpa_supplicant.conf
the configuration file describing all networks that the user wants the computer to
connect to.
wpa_supplicant
the program that directly interacts with the network interface.
wpa_cli
the client program that provides a high-level interface to the functionality of the
daemon.
wpa_passphrase
a utility needed to construct wpa_supplicant.conf files that include encrypted
passwords.
QUICK START
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 line.
INTERFACE TO PCMCIA-CS/CARDMRG
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 /etc/pcmcia/wireless.opts.
Add the following block to the end of start action handler in /etc/pcmcia/wireless:
if [ "$WPA" = "y" -a -x /usr/local/bin/wpa_supplicant ]; then
/usr/local/bin/wpa_supplicant -B -c/etc/wpa_supplicant.conf -i$DEVICE
fi
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
fi
This will make cardmgr start wpa_supplicant when the card is plugged in.
SEE ALSO
wpa_background(8) wpa_supplicant.conf(5) wpa_cli(8) wpa_passphrase(8)
LEGAL
wpa_supplicant is copyright (c) 2003-2014, Jouni Malinen <j@w1.fi> and contributors. All
Rights Reserved.
This program is licensed under the BSD license (the one with advertisement clause
removed).
06 August 2024 WPA_SUPPLICANT(8)