1.\" $OpenBSD: hostapd.8,v 1.14 2007/05/31 19:20:24 jmc Exp $ 2.\" 3.\" Copyright (c) 2004, 2005 Reyk Floeter <reyk@openbsd.org> 4.\" 5.\" Permission to use, copy, modify, and distribute this software for any 6.\" purpose with or without fee is hereby granted, provided that the above 7.\" copyright notice and this permission notice appear in all copies. 8.\" 9.\" THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES 10.\" WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF 11.\" MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR 12.\" ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES 13.\" WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN 14.\" ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF 15.\" OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. 16.\" 17.Dd $Mdocdate: May 31 2007 $ 18.Dt HOSTAPD 8 19.Os 20.Sh NAME 21.Nm hostapd 22.Nd Host Access Point daemon 23.Sh SYNOPSIS 24.Nm hostapd 25.Op Fl dv 26.Oo Xo 27.Fl D Ar macro Ns = Ns Ar value Oc 28.Xc 29.Op Fl f Ar file 30.Sh DESCRIPTION 31.Nm 32is a daemon which allows communication between different 802.11 33wireless access points running in 34.Em Host AP 35mode. 36.Pp 37.Nm 38implements the Inter Access Point Protocol (IAPP). 39Its purpose is to exchange station association updates between access 40points in large wireless networks. 41IAPP has been designed to speed up roaming between different access 42points in the same Extended Service Set (ESS). 43IAPP is described in the IEEE 802.11f standard. 44.Pp 45.Nm 46additionally allows the monitoring and logging of station associations on a 47non-hostap host which is receiving IAPP messages. 48.Pp 49.Nm 50uses two network interfaces on startup specified in the configuration file 51.Xr hostapd.conf 5 . 52The first interface is used to access the Host AP, 53which is a wireless interface running in Host AP mode. 54Host AP mode can be enabled using 55.Xr ifconfig 8 . 56The second interface is used to communicate with other 57.Nm 58in the same broadcast domain or multicast group. 59Usually a wired interface is used to communicate with other 60.Nm . 61.Pp 62The 63.Nm 64will send an 65.Em ADD.notify 66IAPP message if a new station has been associated successfully to the Host AP. 67If the 68.Nm 69receives ADD.notify messages it will request the Host AP 70remove a station which has been associated to another access point. 71.Pp 72.Nm 73may also handle dynamic roaming of IP addresses and routes in 74addition to the standard IAPP ADD.notify behaviour. 75See the section called 76.Sx IP Roaming 77in 78.Xr hostapd.conf 5 79for details. 80.Pp 81The options are as follows: 82.Bl -tag -width Ds 83.It Fl D Ar macro Ns = Ns Ar value 84Define 85.Ar macro 86to be set to 87.Ar value 88on the command line. 89Overrides the definition of 90.Ar macro 91in the configuration file. 92.It Fl d 93Do not daemonize and log to 94.Em stderr . 95.It Fl f Ar file 96Use 97.Ar file 98as the configuration file, instead of the default 99.Pa /etc/hostapd.conf . 100.It Fl v 101Produce more verbose output. 102.El 103.Sh FILES 104.Bl -tag -width "/etc/hostapd.confXXX" -compact 105.It Pa /etc/hostapd.conf 106default 107.Nm 108configuration file 109.El 110.Sh SEE ALSO 111.Xr hostapd.conf 5 , 112.Xr ifconfig 8 113.Rs 114.%R IEEE 802.11f 115.%T Inter Access Point Protocol 116.%D March 2001 117.Re 118.Sh HISTORY 119The 120.Nm 121program first appeared at the 21st Chaos Communication Congress 122(http://www.ccc.de/congress/2004/) and later in 123.Ox 3.8 . 124.Sh AUTHORS 125The 126.Nm 127program was written by 128.An Reyk Floeter Aq reyk@openbsd.org . 129.Sh CAVEATS 130.Nm 131depends on drivers using the net80211 132kernel wireless layer with support of Host AP mode. 133For traditional reasons, 134the 135.Xr wi 4 136driver still uses its own Host AP code in 137.Fn if_wi_hostap , 138which is not supported by 139.Nm . 140.Pp 141The IEEE 802.11 WLAN protocol lacks authentication of management 142frames and is vulnerable to various Denial-of-Service and 143Man-in-the-Middle attacks. 144That should be considered when implementing wireless networks 145with 146.Nm . 147