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>-BddfhKLqqtuvwW</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>
20 <arg>-f<replaceable>output file</replaceable></arg>
24 <title>Overview</title>
27 Wireless networks do not require physical access to the network equipment
28 in the same way as wired networks. This makes it easier for unauthorized
29 users to passively monitor a network and capture all transmitted frames.
30 In addition, unauthorized use of the network is much easier. In many cases,
31 this can happen even without user's explicit knowledge since the wireless
32 LAN adapter may have been configured to automatically join any available
37 Link-layer encryption can be used to provide a layer of security for
38 wireless networks. The original wireless LAN standard, IEEE 802.11,
39 included a simple encryption mechanism, WEP. However, that proved to
40 be flawed in many areas and network protected with WEP cannot be consider
41 secure. IEEE 802.1X authentication and frequently changed dynamic WEP keys
42 can be used to improve the network security, but even that has inherited
43 security issues due to the use of WEP for encryption. Wi-Fi Protected
44 Access and IEEE 802.11i amendment to the wireless LAN standard introduce
45 a much improvement mechanism for securing wireless networks. IEEE 802.11i
46 enabled networks that are using CCMP (encryption mechanism based on strong
47 cryptographic algorithm AES) can finally be called secure used for
48 applications which require efficient protection against unauthorized
52 <para><command>wpa_supplicant</command> is an implementation of
53 the WPA Supplicant component, i.e., the part that runs in the
54 client stations. It implements WPA key negotiation with a WPA
55 Authenticator and EAP authentication with Authentication
56 Server. In addition, it controls the roaming and IEEE 802.11
57 authentication/association of the wireless LAN driver.</para>
59 <para><command>wpa_supplicant</command> is designed to be a
60 "daemon" program that runs in the background and acts as the
61 backend component controlling the wireless
62 connection. <command>wpa_supplicant</command> supports separate
63 frontend programs and an example text-based frontend,
64 <command>wpa_cli</command>, is included with
65 wpa_supplicant.</para>
67 <para>Before wpa_supplicant can do its work, the network interface
68 must be available. That means that the physical device must be
69 present and enabled, and the driver for the device must have be
70 loaded. Note, however, that the '-w' option of the wpa_supplicant
71 daemon instructs the daemon to continue running and to wait for
72 the interface to become available. Without the '-w' option, the
73 daemon will exit immediately if the device is not already
76 <para>After <command>wpa_supplicant</command> has configured the
77 network device, higher level configuration such as DHCP may
78 proceed. There are a variety of ways to integrate wpa_supplicant
79 into a machine's networking scripts, a few of which are described
80 in sections below.</para>
82 <para>The following steps are used when associating with an AP
87 <para><command>wpa_supplicant</command> requests the kernel
88 driver to scan neighboring BSSes</para>
92 <para><command>wpa_supplicant</command> selects a BSS based on
93 its configuration</para>
97 <para><command>wpa_supplicant</command> requests the kernel
98 driver to associate with the chosen BSS</para>
102 <para>If WPA-EAP: integrated IEEE 802.1X Supplicant or
103 external Xsupplicant completes EAP authentication with the
104 authentication server (proxied by the Authenticator in the
109 <para>If WPA-EAP: master key is received from the IEEE 802.1X
114 <para>If WPA-PSK: <command>wpa_supplicant</command> uses PSK
115 as the master session key</para>
119 <para><command>wpa_supplicant</command> completes WPA 4-Way
120 Handshake and Group Key Handshake with the Authenticator
125 <para><command>wpa_supplicant</command> configures encryption
126 keys for unicast and broadcast</para>
130 <para>normal data packets can be transmitted and received</para>
136 <title>Supported Features</title>
137 <para>Supported WPA/IEEE 802.11i features:</para>
140 <para>WPA-PSK ("WPA-Personal")</para>
144 <para>WPA with EAP (e.g., with RADIUS authentication server)
145 ("WPA-Enterprise") Following authentication methods are
146 supported with an integrate IEEE 802.1X Supplicant:</para>
156 <para>EAP-PEAP/MSCHAPv2 (both PEAPv0 and PEAPv1)</para>
161 <para>EAP-PEAP/TLS (both PEAPv0 and PEAPv1)</para>
165 <para>EAP-PEAP/GTC (both PEAPv0 and PEAPv1)</para>
169 <para>EAP-PEAP/OTP (both PEAPv0 and PEAPv1)</para>
173 <para>EAP-PEAP/MD5-Challenge (both PEAPv0 and PEAPv1)</para>
177 <para>EAP-TTLS/EAP-MD5-Challenge</para>
181 <para>EAP-TTLS/EAP-GTC</para>
184 <listitem><para>EAP-TTLS/EAP-OTP</para></listitem>
186 <listitem><para>EAP-TTLS/EAP-MSCHAPv2</para></listitem>
188 <listitem><para>EAP-TTLS/EAP-TLS</para></listitem>
190 <listitem><para>EAP-TTLS/MSCHAPv2</para></listitem>
192 <listitem><para>EAP-TTLS/MSCHAP</para></listitem>
194 <listitem><para>EAP-TTLS/PAP</para></listitem>
196 <listitem><para>EAP-TTLS/CHAP</para></listitem>
198 <listitem><para>EAP-SIM</para></listitem>
200 <listitem><para>EAP-AKA</para></listitem>
202 <listitem><para>EAP-PSK</para></listitem>
204 <listitem><para>EAP-PAX</para></listitem>
206 <listitem><para>LEAP (note: requires special support from
207 the driver for IEEE 802.11 authentication)</para></listitem>
209 <listitem><para>(following methods are supported, but since
210 they do not generate keying material, they cannot be used
211 with WPA or IEEE 802.1X WEP keying)</para></listitem>
213 <listitem><para>EAP-MD5-Challenge </para></listitem>
215 <listitem><para>EAP-MSCHAPv2</para></listitem>
217 <listitem><para>EAP-GTC</para></listitem>
219 <listitem><para>EAP-OTP</para></listitem>
224 <para>key management for CCMP, TKIP, WEP104, WEP40</para>
228 <para>RSN/WPA2 (IEEE 802.11i)</para>
231 <para>pre-authentication</para>
235 <para>PMKSA caching</para>
243 <title>Available Drivers</title>
244 <para>The available drivers to specify with the -D option are:</para>
250 <para>(default) Host AP driver (Intersil Prism2/2.5/3).
251 (this can also be used with Linuxant DriverLoader).</para>
258 <para>Agere Systems Inc. driver (Hermes-I/Hermes-II).</para>
265 <para>MADWIFI 802.11 support (Atheros, etc.).</para>
272 <para>ATMEL AT76C5XXx (USB, PCMCIA).</para>
279 <para>Linux wireless extensions (generic).</para>
284 <term>ndiswrapper</term>
286 <para>Linux ndiswrapper.</para>
291 <term>broadcom</term>
293 <para>Broadcom wl.o driver.</para>
300 <para>Intel ipw2100/2200 driver.</para>
307 <para>wpa_supplicant wired Ethernet driver</para>
314 <para>BSD 802.11 support (Atheros, etc.).</para>
321 <para>Windows NDIS driver.</para>
328 <title>Command Line Options</title>
333 <para>Run daemon in the background.</para>
338 <term>-i ifname</term>
340 <para>Interface to listen on.</para>
345 <term>-c filename</term>
347 <para>Path to configuration file.</para>
352 <term>-P PID_file</term>
354 <para>Path to PID file.</para>
359 <term>-C ctrl_interface</term>
361 <para>Path to ctrl_interface socket (only used if -c is not).</para>
366 <term>-g global ctrl_interface</term>
368 <para>Path to global ctrl_interface socket.</para>
373 <term>-D driver</term>
375 <para>Driver to use. See the available options below.</para>
380 <term>-f output file</term>
382 <para>Log output to specified file instead of stdout.</para>
389 <para>Increase debugging verbosity (-dd even more).</para>
396 <para>Include keys (passwords, etc.) in debug output.</para>
403 <para>Include timestamp in debug messages.</para>
410 <para>Use external IEEE 802.1X Supplicant (e.g.,
411 <command>xsupplicant</command>) (this disables the internal
419 <para>Help. Show a usage message.</para>
426 <para>Show license (GPL and BSD).</para>
433 <para>Decrease debugging verbosity (-qq even less).</para>
439 <para>Show version.</para>
446 <para>wait for interface to be added, if needed. normally,
447 <command>wpa_supplicant</command> will exit if the interface
448 is not there yet.</para>
455 <para>Start describing new interface.</para>
462 <title>Examples</title>
464 <para>In most common cases, <command>wpa_supplicant</command> is
467 <blockquote><programlisting>
468 wpa_supplicant -Bw -c/etc/wpa_supplicant.conf -iwlan0
469 </programlisting></blockquote>
471 <para>This makes the process fork into background and wait for the wlan0
472 interface if it is not available at startup time.</para>
474 <para>The easiest way to debug problems, and to get debug log for
475 bug reports, is to start <command>wpa_supplicant</command> on
476 foreground with debugging enabled:</para>
478 <blockquote><programlisting>
479 wpa_supplicant -c/etc/wpa_supplicant.conf -iwlan0 -d
480 </programlisting></blockquote>
482 <para><command>wpa_supplicant</command> can control multiple
483 interfaces (radios) either by running one process for each
484 interface separately or by running just one process and list of
485 options at command line. Each interface is separated with -N
486 argument. As an example, following command would start
487 wpa_supplicant for two interfaces:</para>
489 <blockquote><programlisting>
491 -c wpa1.conf -i wlan0 -D hostap -N \
492 -c wpa2.conf -i ath0 -D madwifi
493 </programlisting></blockquote>
497 <title>OS Requirements</title>
498 <para>Current hardware/software requirements:</para>
502 <para>Linux kernel 2.4.x or 2.6.x with Linux Wireless
503 Extensions v15 or newer</para>
508 <para>FreeBSD 6-CURRENT</para>
512 <para>Microsoft Windows with WinPcap (at least WinXP, may work
513 with other versions)</para>
519 <title>Supported Drivers</title>
522 <term>Host AP driver for Prism2/2.5/3 (development
523 snapshot/v0.2.x)</term>
525 <para> (http://hostap.epitest.fi/) Driver needs to be set in
526 Managed mode ('iwconfig wlan0 mode managed'). Please note
527 that station firmware version needs to be 1.7.0 or newer to
528 work in WPA mode.</para>
533 <term>Linuxant DriverLoader</term>
535 <para>(http://www.linuxant.com/driverloader/)
536 with Windows NDIS driver for your wlan card supporting WPA.</para>
541 <term>Agere Systems Inc. Linux Driver</term>
543 <para> (http://www.agere.com/support/drivers/) Please note
544 that the driver interface file (driver_hermes.c) and hardware
545 specific include files are not included in the wpa_supplicant
546 distribution. You will need to copy these from the source
547 package of the Agere driver.</para>
552 <term>madwifi driver for cards based on Atheros chip set (ar521x)</term>
554 <para> (http://sourceforge.net/projects/madwifi/) Please
555 note that you will need to modify the wpa_supplicant .config
556 file to use the correct path for the madwifi driver root
557 directory (CFLAGS += -I../madwifi/wpa line in example
563 <term>ATMEL AT76C5XXx driver for USB and PCMCIA cards</term>
565 <para> (http://atmelwlandriver.sourceforge.net/).</para>
570 <term>Linux ndiswrapper</term>
572 <para> (http://ndiswrapper.sourceforge.net/) with Windows
578 <term>Broadcom wl.o driver</term>
580 <para> This is a generic Linux driver for Broadcom IEEE
581 802.11a/g cards. However, it is proprietary driver that is
582 not publicly available except for couple of exceptions, mainly
583 Broadcom-based APs/wireless routers that use Linux. The driver
584 binary can be downloaded, e.g., from Linksys support site
585 (http://www.linksys.com/support/gpl.asp) for Linksys
586 WRT54G. The GPL tarball includes cross-compiler and the needed
587 header file, wlioctl.h, for compiling wpa_supplicant. This
588 driver support in wpa_supplicant is expected to work also with
589 other devices based on Broadcom driver (assuming the driver
590 includes client mode support).</para>
595 <term> Intel ipw2100 driver</term>
597 <para> (http://sourceforge.net/projects/ipw2100/)</para>
602 <term>Intel ipw2200 driver</term>
604 <para> (http://sourceforge.net/projects/ipw2200/)</para>
609 <term>Linux wireless extensions</term>
611 <para>In theory, any driver that supports Linux wireless
612 extensions can be used with IEEE 802.1X (i.e., not WPA) when
613 using ap_scan=0 option in configuration file.</para>
618 <term>Wired Ethernet drivers</term>
620 <para>Use ap_scan=0.</para>
625 <term>BSD net80211 layer (e.g., Atheros driver)</term>
627 <para>At the moment, this is for FreeBSD 6-CURRENT branch.</para>
632 <term>Windows NDIS</term>
634 <para>The current Windows port requires WinPcap
635 (http://winpcap.polito.it/). See README-Windows.txt for more
642 <para>wpa_supplicant was designed to be portable for different
643 drivers and operating systems. Hopefully, support for more wlan
644 cards and OSes will be added in the future. See developer.txt for
645 more information about the design of wpa_supplicant and porting to
646 other drivers. One main goal is to add full WPA/WPA2 support to
647 Linux wireless extensions to allow new drivers to be supported
648 without having to implement new driver-specific interface code in
649 wpa_supplicant.</para>
653 <title>Architecture</title> <para>The
654 <command>wpa_supplicant</command> system consists of the following
659 <term><filename>wpa_supplicant.conf</filename> </term>
661 <para>the configuration file describing all networks that the
662 user wants the computer to connect to. </para>
666 <term><command>wpa_supplicant</command></term>
667 <listitem><para>the program that directly interacts with the
668 network interface. </para></listitem>
671 <term><command>wpa_cli</command></term> <listitem><para> the
672 client program that provides a high-level interface to the
673 functionality of the daemon. </para></listitem>
676 <term><command>wpa_passphrase</command></term>
677 <listitem><para>a utility needed to construct
678 <filename>wpa_supplicant.conf</filename> files that include
679 encrypted passwords.</para></listitem>
685 <title>Quick Start</title>
687 <para>First, make a configuration file, e.g.
688 <filename>/etc/wpa_supplicant.conf</filename>, that describes the networks
689 you are interested in. See <citerefentry>
690 <refentrytitle>wpa_supplicant.conf</refentrytitle>
691 <manvolnum>5</manvolnum>
695 <para>Once the configuration is ready, you can test whether the
696 configuration works by running <command>wpa_supplicant</command>
697 with following command to start it on foreground with debugging
700 <blockquote><programlisting>
701 wpa_supplicant -iwlan0 -c/etc/wpa_supplicant.conf -d
702 </programlisting></blockquote>
704 <para>Assuming everything goes fine, you can start using following
705 command to start <command>wpa_supplicant</command> on background
706 without debugging:</para>
708 <blockquote><programlisting>
709 wpa_supplicant -iwlan0 -c/etc/wpa_supplicant.conf -B
710 </programlisting></blockquote>
712 <para>Please note that if you included more than one driver
713 interface in the build time configuration (.config), you may need
714 to specify which interface to use by including -D<driver
715 name> option on the command line.</para>
717 <!-- XXX at this point, the page could include a little script
718 based on wpa_cli to wait for a connection and then run
724 <title>Interface to pcmcia-cs/cardmrg</title>
726 <para>For example, following small changes to pcmcia-cs scripts
727 can be used to enable WPA support:</para>
729 <para>Add MODE="Managed" and WPA="y" to the network scheme in
730 <filename>/etc/pcmcia/wireless.opts</filename>.</para>
732 <para>Add the following block to the end of 'start' action handler
733 in <filename>/etc/pcmcia/wireless</filename>:</para>
735 <blockquote><programlisting>
736 if [ "$WPA" = "y" -a -x /usr/local/bin/wpa_supplicant ]; then
737 /usr/local/bin/wpa_supplicant -Bw -c/etc/wpa_supplicant.conf -i$DEVICE
739 </programlisting></blockquote>
742 <para>Add the following block to the end of 'stop' action handler
743 (may need to be separated from other actions) in
744 <filename>/etc/pcmcia/wireless</filename>:</para>
746 <blockquote><programlisting>
747 if [ "$WPA" = "y" -a -x /usr/local/bin/wpa_supplicant ]; then
748 killall wpa_supplicant
750 </programlisting></blockquote>
752 <para>This will make <command>cardmgr</command> start
753 <command>wpa_supplicant</command> when the card is plugged
754 in. <command>wpa_supplicant</command> will wait until the
755 interface is set up--either when a static IP address is configured
756 or when DHCP client is started--and will then negotiate keys with
761 <title>See Also</title>
764 <refentrytitle>wpa_background</refentrytitle>
765 <manvolnum>8</manvolnum>
768 <refentrytitle>wpa_supplicant.conf</refentrytitle>
769 <manvolnum>5</manvolnum>
772 <refentrytitle>wpa_cli</refentrytitle>
773 <manvolnum>8</manvolnum>
776 <refentrytitle>wpa_passphrase</refentrytitle>
777 <manvolnum>8</manvolnum>
783 <para>wpa_supplicant is copyright (c) 2003-2005,
784 Jouni Malinen <email>j@w1.fi</email> and
786 All Rights Reserved.</para>
788 <para>This program is dual-licensed under both the GPL version 2
789 and BSD license. Either license may be used at your option.</para>