1 <!doctype refentry PUBLIC "-//OASIS//DTD DocBook V4.1//EN">
5 <refentrytitle>wpa_supplicant</refentrytitle>
6 <manvolnum>8</manvolnum>
9 <refname>wpa_supplicant</refname>
10 <refpurpose>Wi-Fi Protected Access client and IEEE 802.1X supplicant</refpurpose>
14 <command>wpa_supplicant</command>
15 <arg>-BddehLqqvw</arg>
16 <arg>-i<replaceable>ifname</replaceable></arg>
17 <arg>-c<replaceable>config file</replaceable></arg>
18 <arg>-D<replaceable>driver</replaceable></arg>
19 <arg>-P<replaceable>PID_file</replaceable></arg>
23 <title>Overview</title>
26 Wireless networks do not require physical access to the network equipment
27 in the same way as wired networks. This makes it easier for unauthorized
28 users to passively monitor a network and capture all transmitted frames.
29 In addition, unauthorized use of the network is much easier. In many cases,
30 this can happen even without user's explicit knowledge since the wireless
31 LAN adapter may have been configured to automatically join any available
36 Link-layer encryption can be used to provide a layer of security for
37 wireless networks. The original wireless LAN standard, IEEE 802.11,
38 included a simple encryption mechanism, WEP. However, that proved to
39 be flawed in many areas and network protected with WEP cannot be consider
40 secure. IEEE 802.1X authentication and frequently changed dynamic WEP keys
41 can be used to improve the network security, but even that has inherited
42 security issues due to the use of WEP for encryption. Wi-Fi Protected
43 Access and IEEE 802.11i amendment to the wireless LAN standard introduce
44 a much improvement mechanism for securing wireless networks. IEEE 802.11i
45 enabled networks that are using CCMP (encryption mechanism based on strong
46 cryptographic algorithm AES) can finally be called secure used for
47 applications which require efficient protection against unauthorized
51 <para><command>wpa_supplicant</command> is an implementation of
52 the WPA Supplicant component, i.e., the part that runs in the
53 client stations. It implements WPA key negotiation with a WPA
54 Authenticator and EAP authentication with Authentication
55 Server. In addition, it controls the roaming and IEEE 802.11
56 authentication/association of the wireless LAN driver.</para>
58 <para><command>wpa_supplicant</command> is designed to be a
59 "daemon" program that runs in the background and acts as the
60 backend component controlling the wireless
61 connection. <command>wpa_supplicant</command> supports separate
62 frontend programs and an example text-based frontend,
63 <command>wpa_cli</command>, is included with
64 wpa_supplicant.</para>
66 <para>Before wpa_supplicant can do its work, the network interface
67 must be available. That means that the physical device must be
68 present and enabled, and the driver for the device must have be
69 loaded. Note, however, that the '-w' option of the wpa_supplicant
70 daemon instructs the daemon to continue running and to wait for
71 the interface to become available. Without the '-w' option, the
72 daemon will exit immediately if the device is not already
75 <para>After <command>wpa_supplicant</command> has configured the
76 network device, higher level configuration such as DHCP may
77 proceed. There are a variety of ways to integrate wpa_supplicant
78 into a machine's networking scripts, a few of which are described
79 in sections below.</para>
81 <para>The following steps are used when associating with an AP
86 <para><command>wpa_supplicant</command> requests the kernel
87 driver to scan neighboring BSSes</para>
91 <para><command>wpa_supplicant</command> selects a BSS based on
92 its configuration</para>
96 <para><command>wpa_supplicant</command> requests the kernel
97 driver to associate with the chosen BSS</para>
101 <para>If WPA-EAP: integrated IEEE 802.1X Supplicant or
102 external Xsupplicant completes EAP authentication with the
103 authentication server (proxied by the Authenticator in the
108 <para>If WPA-EAP: master key is received from the IEEE 802.1X
113 <para>If WPA-PSK: <command>wpa_supplicant</command> uses PSK
114 as the master session key</para>
118 <para><command>wpa_supplicant</command> completes WPA 4-Way
119 Handshake and Group Key Handshake with the Authenticator
124 <para><command>wpa_supplicant</command> configures encryption
125 keys for unicast and broadcast</para>
129 <para>normal data packets can be transmitted and received</para>
135 <title>Supported Features</title>
136 <para>Supported WPA/IEEE 802.11i features:</para>
139 <para>WPA-PSK ("WPA-Personal")</para>
143 <para>WPA with EAP (e.g., with RADIUS authentication server)
144 ("WPA-Enterprise") Following authentication methods are
145 supported with an integrate IEEE 802.1X Supplicant:</para>
155 <para>EAP-PEAP/MSCHAPv2 (both PEAPv0 and PEAPv1)</para>
160 <para>EAP-PEAP/TLS (both PEAPv0 and PEAPv1)</para>
164 <para>EAP-PEAP/GTC (both PEAPv0 and PEAPv1)</para>
168 <para>EAP-PEAP/OTP (both PEAPv0 and PEAPv1)</para>
172 <para>EAP-PEAP/MD5-Challenge (both PEAPv0 and PEAPv1)</para>
176 <para>EAP-TTLS/EAP-MD5-Challenge</para>
180 <para>EAP-TTLS/EAP-GTC</para>
183 <listitem><para>EAP-TTLS/EAP-OTP</para></listitem>
185 <listitem><para>EAP-TTLS/EAP-MSCHAPv2</para></listitem>
187 <listitem><para>EAP-TTLS/EAP-TLS</para></listitem>
189 <listitem><para>EAP-TTLS/MSCHAPv2</para></listitem>
191 <listitem><para>EAP-TTLS/MSCHAP</para></listitem>
193 <listitem><para>EAP-TTLS/PAP</para></listitem>
195 <listitem><para>EAP-TTLS/CHAP</para></listitem>
197 <listitem><para>EAP-SIM</para></listitem>
199 <listitem><para>EAP-AKA</para></listitem>
201 <listitem><para>EAP-PSK</para></listitem>
203 <listitem><para>EAP-PAX</para></listitem>
205 <listitem><para>LEAP (note: requires special support from
206 the driver for IEEE 802.11 authentication)</para></listitem>
208 <listitem><para>(following methods are supported, but since
209 they do not generate keying material, they cannot be used
210 with WPA or IEEE 802.1X WEP keying)</para></listitem>
212 <listitem><para>EAP-MD5-Challenge </para></listitem>
214 <listitem><para>EAP-MSCHAPv2</para></listitem>
216 <listitem><para>EAP-GTC</para></listitem>
218 <listitem><para>EAP-OTP</para></listitem>
223 <para>key management for CCMP, TKIP, WEP104, WEP40</para>
227 <para>RSN/WPA2 (IEEE 802.11i)</para>
230 <para>pre-authentication</para>
234 <para>PMKSA caching</para>
242 <title>Available Drivers</title>
243 <para>The available drivers to specify with the -D option are:</para>
249 <para>(default) Host AP driver (Intersil Prism2/2.5/3).
250 (this can also be used with Linuxant DriverLoader).</para>
257 <para>Agere Systems Inc. driver (Hermes-I/Hermes-II).</para>
264 <para>MADWIFI 802.11 support (Atheros, etc.).</para>
271 <para>ATMEL AT76C5XXx (USB, PCMCIA).</para>
278 <para>Linux wireless extensions (generic).</para>
283 <term>ndiswrapper</term>
285 <para>Linux ndiswrapper.</para>
290 <term>broadcom</term>
292 <para>Broadcom wl.o driver.</para>
299 <para>Intel ipw2100/2200 driver.</para>
306 <para>wpa_supplicant wired Ethernet driver</para>
313 <para>BSD 802.11 support (Atheros, etc.).</para>
320 <para>Windows NDIS driver.</para>
327 <title>Command Line Options</title>
332 <para>Run daemon in the background.</para>
337 <term>-i ifname</term>
339 <para>Interface to listen on.</para>
344 <term>-c filename</term>
346 <para>Path to configuration file.</para>
351 <term>-P PID_file</term>
353 <para>Path to PID file.</para>
358 <term>-C ctrl_interface</term>
360 <para>Path to ctrl_interface socket (only used if -c is not).</para>
365 <term>-g global ctrl_interface</term>
367 <para>Path to global ctrl_interface socket.</para>
372 <term>-D driver</term>
374 <para>Driver to use. See the available options below.</para>
381 <para>Increase debugging verbosity (-dd even more).</para>
388 <para>Include keys (passwords, etc.) in debug output.</para>
395 <para>Include timestamp in debug messages.</para>
402 <para>Use external IEEE 802.1X Supplicant (e.g.,
403 <command>xsupplicant</command>) (this disables the internal
411 <para>Help. Show a usage message.</para>
418 <para>Show license (GPL and BSD).</para>
425 <para>Decrease debugging verbosity (-qq even less).</para>
431 <para>Show version.</para>
438 <para>wait for interface to be added, if needed. normally,
439 <command>wpa_supplicant</command> will exit if the interface
440 is not there yet.</para>
447 <para>Start describing new interface.</para>
454 <title>Examples</title>
456 <para>In most common cases, <command>wpa_supplicant</command> is
459 <blockquote><programlisting>
460 wpa_supplicant -Bw -c/etc/wpa_supplicant.conf -iwlan0
461 </programlisting></blockquote>
463 <para>This makes the process fork into background and wait for the wlan0
464 interface if it is not available at startup time.</para>
466 <para>The easiest way to debug problems, and to get debug log for
467 bug reports, is to start <command>wpa_supplicant</command> on
468 foreground with debugging enabled:</para>
470 <blockquote><programlisting>
471 wpa_supplicant -c/etc/wpa_supplicant.conf -iwlan0 -d
472 </programlisting></blockquote>
474 <para><command>wpa_supplicant</command> can control multiple
475 interfaces (radios) either by running one process for each
476 interface separately or by running just one process and list of
477 options at command line. Each interface is separated with -N
478 argument. As an example, following command would start
479 wpa_supplicant for two interfaces:</para>
481 <blockquote><programlisting>
483 -c wpa1.conf -i wlan0 -D hostap -N \
484 -c wpa2.conf -i ath0 -D madwifi
485 </programlisting></blockquote>
489 <title>OS Requirements</title>
490 <para>Current hardware/software requirements:</para>
494 <para>Linux kernel 2.4.x or 2.6.x with Linux Wireless
495 Extensions v15 or newer</para>
500 <para>FreeBSD 6-CURRENT</para>
504 <para>Microsoft Windows with WinPcap (at least WinXP, may work
505 with other versions)</para>
511 <title>Supported Drivers</title>
514 <term>Host AP driver for Prism2/2.5/3 (development
515 snapshot/v0.2.x)</term>
517 <para> (http://hostap.epitest.fi/) Driver needs to be set in
518 Managed mode ('iwconfig wlan0 mode managed'). Please note
519 that station firmware version needs to be 1.7.0 or newer to
520 work in WPA mode.</para>
525 <term>Linuxant DriverLoader</term>
527 <para>(http://www.linuxant.com/driverloader/)
528 with Windows NDIS driver for your wlan card supporting WPA.</para>
533 <term>Agere Systems Inc. Linux Driver</term>
535 <para> (http://www.agere.com/support/drivers/) Please note
536 that the driver interface file (driver_hermes.c) and hardware
537 specific include files are not included in the wpa_supplicant
538 distribution. You will need to copy these from the source
539 package of the Agere driver.</para>
544 <term>madwifi driver for cards based on Atheros chip set (ar521x)</term>
546 <para> (http://sourceforge.net/projects/madwifi/) Please
547 note that you will need to modify the wpa_supplicant .config
548 file to use the correct path for the madwifi driver root
549 directory (CFLAGS += -I../madwifi/wpa line in example
555 <term>ATMEL AT76C5XXx driver for USB and PCMCIA cards</term>
557 <para> (http://atmelwlandriver.sourceforge.net/).</para>
562 <term>Linux ndiswrapper</term>
564 <para> (http://ndiswrapper.sourceforge.net/) with Windows
570 <term>Broadcom wl.o driver</term>
572 <para> This is a generic Linux driver for Broadcom IEEE
573 802.11a/g cards. However, it is proprietary driver that is
574 not publicly available except for couple of exceptions, mainly
575 Broadcom-based APs/wireless routers that use Linux. The driver
576 binary can be downloaded, e.g., from Linksys support site
577 (http://www.linksys.com/support/gpl.asp) for Linksys
578 WRT54G. The GPL tarball includes cross-compiler and the needed
579 header file, wlioctl.h, for compiling wpa_supplicant. This
580 driver support in wpa_supplicant is expected to work also with
581 other devices based on Broadcom driver (assuming the driver
582 includes client mode support).</para>
587 <term> Intel ipw2100 driver</term>
589 <para> (http://sourceforge.net/projects/ipw2100/)</para>
594 <term>Intel ipw2200 driver</term>
596 <para> (http://sourceforge.net/projects/ipw2200/)</para>
601 <term>Linux wireless extensions</term>
603 <para>In theory, any driver that supports Linux wireless
604 extensions can be used with IEEE 802.1X (i.e., not WPA) when
605 using ap_scan=0 option in configuration file.</para>
610 <term>Wired Ethernet drivers</term>
612 <para>Use ap_scan=0.</para>
617 <term>BSD net80211 layer (e.g., Atheros driver)</term>
619 <para>At the moment, this is for FreeBSD 6-CURRENT branch.</para>
624 <term>Windows NDIS</term>
626 <para>The current Windows port requires WinPcap
627 (http://winpcap.polito.it/). See README-Windows.txt for more
634 <para>wpa_supplicant was designed to be portable for different
635 drivers and operating systems. Hopefully, support for more wlan
636 cards and OSes will be added in the future. See developer.txt for
637 more information about the design of wpa_supplicant and porting to
638 other drivers. One main goal is to add full WPA/WPA2 support to
639 Linux wireless extensions to allow new drivers to be supported
640 without having to implement new driver-specific interface code in
641 wpa_supplicant.</para>
645 <title>Architecture</title> <para>The
646 <command>wpa_supplicant</command> system consists of the following
651 <term><filename>wpa_supplicant.conf</filename> </term>
653 <para>the configuration file describing all networks that the
654 user wants the computer to connect to. </para>
658 <term><command>wpa_supplicant</command></term>
659 <listitem><para>the program that directly interacts with the
660 network interface. </para></listitem>
663 <term><command>wpa_cli</command></term> <listitem><para> the
664 client program that provides a high-level interface to the
665 functionality of the daemon. </para></listitem>
668 <term><command>wpa_passphrase</command></term>
669 <listitem><para>a utility needed to construct
670 <filename>wpa_supplicant.conf</filename> files that include
671 encrypted passwords.</para></listitem>
677 <title>Quick Start</title>
679 <para>First, make a configuration file, e.g.
680 <filename>/etc/wpa_supplicant.conf</filename>, that describes the networks
681 you are interested in. See <citerefentry>
682 <refentrytitle>wpa_supplicant.conf</refentrytitle>
683 <manvolnum>5</manvolnum>
687 <para>Once the configuration is ready, you can test whether the
688 configuration works by running <command>wpa_supplicant</command>
689 with following command to start it on foreground with debugging
692 <blockquote><programlisting>
693 wpa_supplicant -iwlan0 -c/etc/wpa_supplicant.conf -d
694 </programlisting></blockquote>
696 <para>Assuming everything goes fine, you can start using following
697 command to start <command>wpa_supplicant</command> on background
698 without debugging:</para>
700 <blockquote><programlisting>
701 wpa_supplicant -iwlan0 -c/etc/wpa_supplicant.conf -B
702 </programlisting></blockquote>
704 <para>Please note that if you included more than one driver
705 interface in the build time configuration (.config), you may need
706 to specify which interface to use by including -D<driver
707 name> option on the command line.</para>
709 <!-- XXX at this point, the page could include a little script
710 based on wpa_cli to wait for a connection and then run
716 <title>Interface to pcmcia-cs/cardmrg</title>
718 <para>For example, following small changes to pcmcia-cs scripts
719 can be used to enable WPA support:</para>
721 <para>Add MODE="Managed" and WPA="y" to the network scheme in
722 <filename>/etc/pcmcia/wireless.opts</filename>.</para>
724 <para>Add the following block to the end of 'start' action handler
725 in <filename>/etc/pcmcia/wireless</filename>:</para>
727 <blockquote><programlisting>
728 if [ "$WPA" = "y" -a -x /usr/local/bin/wpa_supplicant ]; then
729 /usr/local/bin/wpa_supplicant -Bw -c/etc/wpa_supplicant.conf -i$DEVICE
731 </programlisting></blockquote>
734 <para>Add the following block to the end of 'stop' action handler
735 (may need to be separated from other actions) in
736 <filename>/etc/pcmcia/wireless</filename>:</para>
738 <blockquote><programlisting>
739 if [ "$WPA" = "y" -a -x /usr/local/bin/wpa_supplicant ]; then
740 killall wpa_supplicant
742 </programlisting></blockquote>
744 <para>This will make <command>cardmgr</command> start
745 <command>wpa_supplicant</command> when the card is plugged
746 in. <command>wpa_supplicant</command> will wait until the
747 interface is set up--either when a static IP address is configured
748 or when DHCP client is started--and will then negotiate keys with
753 <title>See Also</title>
756 <refentrytitle>wpa_background</refentrytitle>
757 <manvolnum>8</manvolnum>
760 <refentrytitle>wpa_supplicant.conf</refentrytitle>
761 <manvolnum>5</manvolnum>
764 <refentrytitle>wpa_cli</refentrytitle>
765 <manvolnum>8</manvolnum>
768 <refentrytitle>wpa_passphrase</refentrytitle>
769 <manvolnum>8</manvolnum>
775 <para>wpa_supplicant is copyright (c) 2003-2005,
776 Jouni Malinen <email>j@w1.fi</email> and
778 All Rights Reserved.</para>
780 <para>This program is dual-licensed under both the GPL version 2
781 and BSD license. Either license may be used at your option.</para>