<!doctype refentry PUBLIC "-//OASIS//DTD DocBook V4.1//EN">
<refentry>
<refmeta>
<refentrytitle>wpa_supplicant</refentrytitle>
<manvolnum>8</manvolnum>
</refmeta>
<refnamediv>
<refname>wpa_supplicant</refname>
<refpurpose>Wi-Fi Protected Access client and IEEE 802.1X supplicant</refpurpose>
</refnamediv>
<refsynopsisdiv>
<cmdsynopsis>
<command>wpa_supplicant</command>
<arg>-BddfhKLqqsTtuvW</arg>
<arg>-i<replaceable>ifname</replaceable></arg>
<arg>-c<replaceable>config file</replaceable></arg>
<arg>-D<replaceable>driver</replaceable></arg>
<arg>-P<replaceable>PID_file</replaceable></arg>
<arg>-f<replaceable>output file</replaceable></arg>
</cmdsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Overview</title>
<para>
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.
</para>
<para>
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.
</para>
<para><command>wpa_supplicant</command> 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.</para>
<para><command>wpa_supplicant</command> is designed to be a
"daemon" program that runs in the background and acts as the
backend component controlling the wireless
connection. <command>wpa_supplicant</command> supports separate
frontend programs and an example text-based frontend,
<command>wpa_cli</command>, is included with
wpa_supplicant.</para>
<para>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.</para>
<para>After <command>wpa_supplicant</command> 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.</para>
<para>The following steps are used when associating with an AP
using WPA:</para>
<itemizedlist>
<listitem>
<para><command>wpa_supplicant</command> requests the kernel
driver to scan neighboring BSSes</para>
</listitem>
<listitem>
<para><command>wpa_supplicant</command> selects a BSS based on
its configuration</para>
</listitem>
<listitem>
<para><command>wpa_supplicant</command> requests the kernel
driver to associate with the chosen BSS</para>
</listitem>
<listitem>
<para>If WPA-EAP: integrated IEEE 802.1X Supplicant
completes EAP authentication with the
authentication server (proxied by the Authenticator in the
AP)</para>
</listitem>
<listitem>
<para>If WPA-EAP: master key is received from the IEEE 802.1X
Supplicant</para>
</listitem>
<listitem>
<para>If WPA-PSK: <command>wpa_supplicant</command> uses PSK
as the master session key</para>
</listitem>
<listitem>
<para><command>wpa_supplicant</command> completes WPA 4-Way
Handshake and Group Key Handshake with the Authenticator
(AP)</para>
</listitem>
<listitem>
<para><command>wpa_supplicant</command> configures encryption
keys for unicast and broadcast</para>
</listitem>
<listitem>
<para>normal data packets can be transmitted and received</para>
</listitem>
</itemizedlist>
</refsect1>
<refsect1>
<title>Supported Features</title>
<para>Supported WPA/IEEE 802.11i features:</para>
<itemizedlist>
<listitem>
<para>WPA-PSK ("WPA-Personal")</para>
</listitem>
<listitem>
<para>WPA with EAP (e.g., with RADIUS authentication server)
("WPA-Enterprise") Following authentication methods are
supported with an integrate IEEE 802.1X Supplicant:</para>
<itemizedlist>
<listitem>
<para>EAP-TLS</para>
</listitem>
</itemizedlist>
<itemizedlist>
<listitem>
<para>EAP-PEAP/MSCHAPv2 (both PEAPv0 and PEAPv1)</para>
</listitem>
<listitem>
<para>EAP-PEAP/TLS (both PEAPv0 and PEAPv1)</para>
</listitem>
<listitem>
<para>EAP-PEAP/GTC (both PEAPv0 and PEAPv1)</para>
</listitem>
<listitem>
<para>EAP-PEAP/OTP (both PEAPv0 and PEAPv1)</para>
</listitem>
<listitem>
<para>EAP-PEAP/MD5-Challenge (both PEAPv0 and PEAPv1)</para>
</listitem>
<listitem>
<para>EAP-TTLS/EAP-MD5-Challenge</para>
</listitem>
<listitem>
<para>EAP-TTLS/EAP-GTC</para>
</listitem>
<listitem><para>EAP-TTLS/EAP-OTP</para></listitem>
<listitem><para>EAP-TTLS/EAP-MSCHAPv2</para></listitem>
<listitem><para>EAP-TTLS/EAP-TLS</para></listitem>
<listitem><para>EAP-TTLS/MSCHAPv2</para></listitem>
<listitem><para>EAP-TTLS/MSCHAP</para></listitem>
<listitem><para>EAP-TTLS/PAP</para></listitem>
<listitem><para>EAP-TTLS/CHAP</para></listitem>
<listitem><para>EAP-SIM</para></listitem>
<listitem><para>EAP-AKA</para></listitem>
<listitem><para>EAP-PSK</para></listitem>
<listitem><para>EAP-PAX</para></listitem>
<listitem><para>LEAP (note: requires special support from
the driver for IEEE 802.11 authentication)</para></listitem>
<listitem><para>(following methods are supported, but since
they do not generate keying material, they cannot be used
with WPA or IEEE 802.1X WEP keying)</para></listitem>
<listitem><para>EAP-MD5-Challenge </para></listitem>
<listitem><para>EAP-MSCHAPv2</para></listitem>
<listitem><para>EAP-GTC</para></listitem>
<listitem><para>EAP-OTP</para></listitem>
</itemizedlist>
</listitem>
<listitem>
<para>key management for CCMP, TKIP, WEP104, WEP40</para>
</listitem>
<listitem>
<para>RSN/WPA2 (IEEE 802.11i)</para>
<itemizedlist>
<listitem>
<para>pre-authentication</para>
</listitem>
<listitem>
<para>PMKSA caching</para>
</listitem>
</itemizedlist>
</listitem>
</itemizedlist>
</refsect1>
<refsect1>
<title>Available Drivers</title>
<para>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
(<emphasis>wpa_supplicant -h</emphasis>).</para>
<variablelist>
<varlistentry>
<term>nl80211</term>
<listitem>
<para>Uses the modern Linux nl80211/cfg80211 netlink-based
interface (most new drivers).</para>
</listitem>
</varlistentry>
<varlistentry>
<term>wext</term>
<listitem>
<para>Uses the legacy Linux wireless extensions ioctl-based
interface (older hardware/drivers).</para>
</listitem>
</varlistentry>
<varlistentry>
<term>wired</term>
<listitem>
<para>wpa_supplicant wired Ethernet driver</para>
</listitem>
</varlistentry>
<varlistentry>
<term>roboswitch</term>
<listitem>
<para>wpa_supplicant Broadcom switch driver</para>
</listitem>
</varlistentry>
<varlistentry>
<term>bsd</term>
<listitem>
<para>BSD 802.11 support (Atheros, etc.).</para>
</listitem>
</varlistentry>
<varlistentry>
<term>ndis</term>
<listitem>
<para>Windows NDIS driver.</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Command Line Options</title>
<para>Most command line options have global scope. Some are given per
interface, and are only valid if at least one <option>-i</option> option
is specified, otherwise they're ignored. Option groups for different
interfaces must be separated by <option>-N</option> option.</para>
<variablelist>
<varlistentry>
<term>-b br_ifname</term>
<listitem>
<para>Optional bridge interface name. (Per interface)</para>
</listitem>
</varlistentry>
<varlistentry>
<term>-B</term>
<listitem>
<para>Run daemon in the background.</para>
</listitem>
</varlistentry>
<varlistentry>
<term>-c filename</term>
<listitem>
<para>Path to configuration file. (Per interface)</para>
</listitem>
</varlistentry>
<varlistentry>
<term>-C ctrl_interface</term>
<listitem>
<para>Path to ctrl_interface socket (Per interface. Only used if
<option>-c</option> is not).</para>
</listitem>
</varlistentry>
<varlistentry>
<term>-i ifname</term>
<listitem>
<para>Interface to listen on. Multiple instances of this option can
be present, one per interface, separated by <option>-N</option>
option (see below).</para>
</listitem>
</varlistentry>
<varlistentry>
<term>-d</term>
<listitem>
<para>Increase debugging verbosity (<option>-dd</option> even
more).</para>
</listitem>
</varlistentry>
<varlistentry>
<term>-D driver</term>
<listitem>
<para>Driver to use (can be multiple drivers: nl80211,wext).
(Per interface, see the available options below.)</para>
</listitem>
</varlistentry>
<varlistentry>
<term>-e entropy file</term>
<listitem>
<para>File for <command>wpa_supplicant</command> to use to
maintain its internal entropy store in over restarts.</para>
</listitem>
</varlistentry>
<varlistentry>
<term>-f output file</term>
<listitem>
<para>Log output to specified file instead of stdout. (This
is only available if <command>wpa_supplicant</command> was
built with the <literal>CONFIG_DEBUG_FILE</literal>
option.)</para>
</listitem>
</varlistentry>
<varlistentry>
<term>-g global ctrl_interface</term>
<listitem>
<para>Path to global ctrl_interface socket. If specified, interface
definitions may be omitted.</para>
</listitem>
</varlistentry>
<varlistentry>
<term>-K</term>
<listitem>
<para>Include keys (passwords, etc.) in debug output.</para>
</listitem>
</varlistentry>
<varlistentry>
<term>-h</term>
<listitem>
<para>Help. Show a usage message.</para>
</listitem>
</varlistentry>
<varlistentry>
<term>-L</term>
<listitem>
<para>Show license (BSD).</para>
</listitem>
</varlistentry>
<varlistentry>
<term>-o override driver</term>
<listitem>
<para>Override the driver parameter for new
interfaces.</para>
</listitem>
</varlistentry>
<varlistentry>
<term>-O override ctrl_interface</term>
<listitem>
<para>Override the ctrl_interface parameter for new
interfaces.</para>
</listitem>
</varlistentry>
<varlistentry>
<term>-p</term>
<listitem>
<para>Driver parameters. (Per interface)</para>
</listitem>
</varlistentry>
<varlistentry>
<term>-P PID_file</term>
<listitem>
<para>Path to PID file.</para>
</listitem>
</varlistentry>
<varlistentry>
<term>-q</term>
<listitem>
<para>Decrease debugging verbosity (<option>-qq</option> even
less).</para>
</listitem>
</varlistentry>
<varlistentry>
<term>-s</term>
<listitem>
<para>Log output to syslog instead of stdout. (This is only
available if <command>wpa_supplicant</command> was built
with the <literal>CONFIG_DEBUG_SYSLOG</literal>
option.)</para>
</listitem>
</varlistentry>
<varlistentry>
<term>-T</term>
<listitem>
<para>Log output to Linux tracing in addition to any other
destinations. (This is only available
if <command>wpa_supplicant</command> was built with
the <literal>CONFIG_DEBUG_LINUX_TRACING</literal>
option.)</para>
</listitem>
</varlistentry>
<varlistentry>
<term>-t</term>
<listitem>
<para>Include timestamp in debug messages.</para>
</listitem>
</varlistentry>
<varlistentry>
<term>-u</term>
<listitem>
<para>Enable DBus control interface. If enabled, interface
definitions may be omitted. (This is only available
if <command>wpa_supplicant</command> was built with
the <literal>CONFIG_CTRL_IFACE_DBUS_NEW</literal> option.)</para>
</listitem>
</varlistentry>
<varlistentry>
<term>-v</term>
<listitem>
<para>Show version.</para>
</listitem>
</varlistentry>
<varlistentry>
<term>-W</term>
<listitem>
<para>Wait for a control interface monitor before starting.</para>
</listitem>
</varlistentry>
<varlistentry>
<term>-N</term>
<listitem>
<para>Start describing new interface.</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Examples</title>
<para>In most common cases, <command>wpa_supplicant</command> is
started with:</para>
<blockquote><programlisting>
wpa_supplicant -B -c/etc/wpa_supplicant.conf -iwlan0
</programlisting></blockquote>
<para>This makes the process fork into background.</para>
<para>The easiest way to debug problems, and to get debug log for
bug reports, is to start <command>wpa_supplicant</command> on
foreground with debugging enabled:</para>
<blockquote><programlisting>
wpa_supplicant -c/etc/wpa_supplicant.conf -iwlan0 -d
</programlisting></blockquote>
<para>If the specific driver wrapper is not known beforehand, it is
possible to specify multiple comma separated driver wrappers on the command
line. <command>wpa_supplicant</command> will use the first driver
wrapper that is able to initialize the interface.</para>
<blockquote><programlisting>
wpa_supplicant -Dnl80211,wext -c/etc/wpa_supplicant.conf -iwlan0
</programlisting></blockquote>
<para><command>wpa_supplicant</command> 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:</para>
<blockquote><programlisting>
wpa_supplicant \
-c wpa1.conf -i wlan0 -D nl80211 -N \
-c wpa2.conf -i ath0 -D wext
</programlisting></blockquote>
</refsect1>
<refsect1>
<title>OS Requirements</title>
<para>Current hardware/software requirements:</para>
<itemizedlist>
<listitem>
<para>Linux kernel 2.6.30 or higher with
nl80211/cfg80211 support</para>
</listitem>
<listitem>
<para>Linux kernel 2.4.x or higher with Linux Wireless
Extensions v15 or newer</para>
</listitem>
<listitem>
<para>FreeBSD 6-CURRENT</para>
</listitem>
<listitem>
<para>Microsoft Windows with WinPcap (at least WinXP, may work
with other versions)</para>
</listitem>
</itemizedlist>
</refsect1>
<refsect1>
<title>Supported Drivers</title>
<variablelist>
<varlistentry>
<term>Linux nl80211/cfg80211</term>
<listitem>
<para>This is the preferred driver for Linux.</para>
</listitem>
</varlistentry>
<varlistentry>
<term>Linux wireless extensions</term>
<listitem>
<para>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.</para>
</listitem>
</varlistentry>
<varlistentry>
<term>Wired Ethernet drivers</term>
<listitem>
<para>Use ap_scan=0.</para>
</listitem>
</varlistentry>
<varlistentry>
<term>BSD net80211 layer (e.g., Atheros driver)</term>
<listitem>
<para>At the moment, this is for FreeBSD 6-CURRENT branch.</para>
</listitem>
</varlistentry>
<varlistentry>
<term>Windows NDIS</term>
<listitem>
<para>The current Windows port requires WinPcap
(http://winpcap.polito.it/). See README-Windows.txt for more
information.</para>
</listitem>
</varlistentry>
</variablelist>
<para>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.</para>
</refsect1>
<refsect1>
<title>Architecture</title> <para>The
<command>wpa_supplicant</command> system consists of the following
components:</para>
<variablelist>
<varlistentry>
<term><filename>wpa_supplicant.conf</filename> </term>
<listitem>
<para>the configuration file describing all networks that the
user wants the computer to connect to. </para>
</listitem>
</varlistentry>
<varlistentry>
<term><command>wpa_supplicant</command></term>
<listitem><para>the program that directly interacts with the
network interface. </para></listitem>
</varlistentry>
<varlistentry>
<term><command>wpa_cli</command></term> <listitem><para> the
client program that provides a high-level interface to the
functionality of the daemon. </para></listitem>
</varlistentry>
<varlistentry>
<term><command>wpa_passphrase</command></term>
<listitem><para>a utility needed to construct
<filename>wpa_supplicant.conf</filename> files that include
encrypted passwords.</para></listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Quick Start</title>
<para>First, make a configuration file, e.g.
<filename>/etc/wpa_supplicant.conf</filename>, that describes the networks
you are interested in. See <citerefentry>
<refentrytitle>wpa_supplicant.conf</refentrytitle>
<manvolnum>5</manvolnum>
</citerefentry>
for details.</para>
<para>Once the configuration is ready, you can test whether the
configuration works by running <command>wpa_supplicant</command>
with following command to start it on foreground with debugging
enabled:</para>
<blockquote><programlisting>
wpa_supplicant -iwlan0 -c/etc/wpa_supplicant.conf -d
</programlisting></blockquote>
<para>Assuming everything goes fine, you can start using following
command to start <command>wpa_supplicant</command> on background
without debugging:</para>
<blockquote><programlisting>
wpa_supplicant -iwlan0 -c/etc/wpa_supplicant.conf -B
</programlisting></blockquote>
<para>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.</para>
<!-- XXX at this point, the page could include a little script
based on wpa_cli to wait for a connection and then run
dhclient -->
</refsect1>
<refsect1>
<title>Interface to pcmcia-cs/cardmrg</title>
<para>For example, following small changes to pcmcia-cs scripts
can be used to enable WPA support:</para>
<para>Add MODE="Managed" and WPA="y" to the network scheme in
<filename>/etc/pcmcia/wireless.opts</filename>.</para>
<para>Add the following block to the end of <emphasis>start</emphasis>
action handler in <filename>/etc/pcmcia/wireless</filename>:</para>
<blockquote><programlisting>
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
</programlisting></blockquote>
<para>Add the following block to the end of <emphasis>stop</emphasis>
action handler (may need to be separated from other actions) in
<filename>/etc/pcmcia/wireless</filename>:</para>
<blockquote><programlisting>
if [ "$WPA" = "y" -a -x /usr/local/bin/wpa_supplicant ]; then
killall wpa_supplicant
fi
</programlisting></blockquote>
<para>This will make <command>cardmgr</command> start
<command>wpa_supplicant</command> when the card is plugged
in.</para>
</refsect1>
<refsect1>
<title>See Also</title>
<para>
<citerefentry>
<refentrytitle>wpa_background</refentrytitle>
<manvolnum>8</manvolnum>
</citerefentry>
<citerefentry>
<refentrytitle>wpa_supplicant.conf</refentrytitle>
<manvolnum>5</manvolnum>
</citerefentry>
<citerefentry>
<refentrytitle>wpa_cli</refentrytitle>
<manvolnum>8</manvolnum>
</citerefentry>
<citerefentry>
<refentrytitle>wpa_passphrase</refentrytitle>
<manvolnum>8</manvolnum>
</citerefentry>
</para>
</refsect1>
<refsect1>
<title>Legal</title>
<para>wpa_supplicant is copyright (c) 2003-2019,
Jouni Malinen <email>j@w1.fi</email> and
contributors.
All Rights Reserved.</para>
<para>This program is licensed under the BSD license (the one with
advertisement clause removed).</para>
</refsect1>
</refentry>