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Wireless Utilities

As already explained at wireless.overview the Linux IEEE 802.11 subsystem is fragmented. The available tools depend entirely on your driver. Wireless devices have an API different from that of Ethernet devices because the specifications of IEEE 802.11 regulate quite precisely the whole communications process, so it makes sense to NOT implement this requirements in each driver but only once for all drivers and also because there is the problem of the diverging frequency regulations world wide.

mac80211-based drivers (ath9k, b43, brcmfmac, etc.)


iwconfig (and /proc/net/wireless) is the configuration utility for the now obsolete WEXT API, which is scheduled for removal. Use iw or iwinfo.


iwinfo is a CLI frontend to the custom library, which assembles information from various places. It is also used by LuCI

  • When in AP-mode, obtain a list of connected clients in STA-mode:
    iwinfo wlan0/wl0/ath0 assoclist


iw is the configuration utility for the nl80211 API.

  • Add a new virtual interface with the given configuration:
    iw dev <devname> interface add <name> type <type> [mesh_id <meshid>] [4addr on|off] [flags <flag>*]
    Valid interface types are: managed, ibss, monitor, mesh, wds. See →wireless modes
    The flags are only used for monitor interfaces, valid flags are: none, fcsfail, control, otherbss, cook
  • Add a new virtual interface with the given configuration:
    iw phy <phyname> interface add <name> type <type> [flags <flag>*]
  • Getting the currently set regulatory domain:
    iw reg get
  • When in AP-mode, obtain a list of connected clients in STA-mode:
    iw dev wlan0 station dump
  • Setting regulatory domain. Set your country ISO 3166-1 alpha-2 in capital letters:
    iw reg set XX

Note: The ath9k driver (and all other softmac drivers?) sets its own regulatory restrictions based on its EEPROM, i.e. the ART (Atheros Radio Test) partition on flash. Setting the domain from userland can only further restrict the regulatory settings. So if EEPROM says Japan, you can use all 14 channels, if you then set it to US, you can use merely the 12. It does not work the other way around, i.e. if EEPROM says US, you only can use the allowed 12 channels, no matter what you set in userspace! The value 98 represents a synthesized regulatory domain, based on the intersection of the available source of regulatory information (which can include the EEPROM, the userland setting, and a country IE from your AP).


The mac80211 subsystem moves all aspects of master mode (a.k.a. AP mode) into user space, thus it depends on hostapd (also read Hostapd) to

  • handle authenticating clients,
  • set encryption keys,
  • establishing key rotation policy,
  • handle other aspects of the wireless infrastructure.

Due to this, the old method of issuing iwconfig <wireless interface> mode master no longer works. Userspace programs like hostapd now use netlink (the nl80211 driver) to create a master mode interface for your traffic and a monitor mode interface for receiving and transmitting management frames.


Is a hostapd + wpa_supplicant multicall binary.

hostapd-mini and wpad-mini

Are stripped down versions without OpenSSL dependency.

Available Packages
hostapd 232.885 This package contains a full featured IEEE 802.1x/WPA/EAP/RADIUS Authenticator.
/etc/hostapd.conf is generated by
hostapd-utils 10.198 This package contains a command line utility to control the IEEE 802.1x/WPA/EAP/RADIUS Authenticator.
hostapd-mini 134.598 This package contains a minimal IEEE 802.1x/WPA Authenticator (Alles Version: 20110527-2)
wpad 355.463 This package contains a full featured IEEE 802.1x/WPA/EAP/RADIUS Authenticator and Supplicant
wpa-supplicant 220.602 WPA Supplicant
wpa-cli 19.887 WPA Supplicant command line interface
wpad-mini 203.085 This package contains a minimal IEEE 802.1x/WPA Authenticator and Supplicant (WPA-PSK only).
wpa-supplicant-mini 111.984 WPA Supplicant (minimal version)
libnl-tiny 13.529 This package contains a stripped down version of libnl; all packages in hostapd depend on it
libnl 107.504 This package contains a library for applications dealing with netlink sockets
xsupplicant 122.996 This software allows a host to authenticate with a RADIUS server using 802.1x and various EAP protocols.
wpad package is a full featured IEEE 802.1x authenticator/supplicant (WPA/EAP/RADIUS), while wpad-mini only supports WPA-PSK (Pre-shared key). wpad obsoletes hostapd and wpa_supplicant as it offers both authentication service for the access point mode and supplicant services for the wireless client mode in one package.

Also see atheros.and.generic.mac80211.wifi


  • As far as I understand, wpad is a wrapper around hostapd with multicall support and wpa_supplicant built.
  • Both wpad and wpad-mini are just wrappers around 'hostapd' with support packages, see
    • wpad-mini is the base system with only WPA(2)-PSK authentication.
    • wpad supports IEEE 802.1x/WPA/EAP/RADIUS (adds the 'WPA supplicant' package with OpenSSL library)
  • The hostapd-utils just adds a small hostapd_cli command line tool for messaging with the daemon.
  • Actually, it's the other way around: hostapd is symlink to wpad, cf. /usr/sbin/hostapd → wpad.
  • Turning off debugging for wpa_supplicant decreased size of wpad-package from ~365 KiB to ~286 KiB. Turning off debugging for hostapd did nothing. Because it's a different binary, not included in wpad.

drivers without cfg80211-support

Atheros proprietary (madwifi)

  • When in AP-mode, obtain a list of connected clients in STA-mode
    wlanconfig ath0 list sta

Broadcom proprietary (wl)

  • When in AP-mode, obtain a list of connected clients in STA-mode:
    wl assoclist
    wl sta_info macaddr
doc/howto/wireless.utilities.txt · Last modified: 2014/07/07 21:31 by valentt