Host Access Point daemon
hostapd is a daemon which allows
communication between different 802.11 wireless access points running in
hostapd implements the Inter Access Point
Protocol (IAPP). Its purpose is to exchange station association updates
between access points in large wireless networks. IAPP has been designed to
speed up roaming between different access points in the same Extended
Service Set (ESS). IAPP is described in the IEEE 802.11f standard.
hostapd additionally allows the monitoring
and logging of station associations on a non-hostap host which is receiving
hostapd uses two network interfaces on
startup specified in the configuration file
hostapd.conf(5). The first interface is used to access the
Host AP, which is a wireless interface running in Host AP mode. Host AP mode
can be enabled using
ifconfig(8). The second interface is used to communicate with other
hostapd in the same broadcast domain or multicast
group. Usually a wired interface is used to communicate with other
hostapd broadcasts an
IAPP message when a new station is associated to the Host AP. When
hostapd receives an ADD.notify message, it tells the
Host AP to remove the specified station.
hostapd may also handle dynamic roaming of
IP addresses and routes in addition to the standard IAPP ADD.notify
behaviour. See the section called IP Roaming in
hostapd.conf(5) for details.
The options are as follows:
- Define macro to be set to value on the command line. Overrides the definition of macro in the configuration file.
- Do not daemonize and log to stderr.
- Use file as the configuration file, instead of the default /etc/hostapd.conf.
- Produce more verbose output.
Inter Access Point Protocol, IEEE 802.11f, March 2001.
hostapd program first appeared at the
21st Chaos Communication Congress
and later in OpenBSD 3.8.
hostapd program was written by
hostapd depends on drivers using the
net80211 kernel wireless layer with support of Host AP mode. For traditional
reasons, the wi(4) driver still uses its own Host AP code in
if_wi_hostap(), which is not supported by
The IEEE 802.11 WLAN protocol lacks authentication of management
frames and is vulnerable to various denial of service and man-in-the-middle
attacks. That should be considered when implementing wireless networks with