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WLAN

Wireless Local Area Network (WLAN) technology enables network communication over radio waves. The IEEE 802.11 family of standards defines WLAN protocols, with Wi-Fi being the most widely adopted trademarked implementation.

802.11 Standards

Standard Frequency Max Data Rate Notes
802.11b 2.4 GHz 11 Mbps Legacy, widely compatible
802.11g 2.4 GHz 54 Mbps Improved 2.4 GHz
802.11n 2.4/5 GHz 600 Mbps MIMO, 2x2 streams
802.11ac (Wi-Fi 5) 5 GHz 3.5 Gbps MU-MIMO, wider channels
802.11ax (Wi-Fi 6) 2.4/5 GHz 9.6 Gbps OFDMA, better efficiency
802.11ax (Wi-Fi 6E) 6 GHz Higher 6 GHz band
802.11be (Wi-Fi 7) 2.4/5/6 GHz 46 Gbps 320 MHz channels, ML

Linux Wireless Tools

ip and iw

Modern tools for wireless interface management:

iw dev                          # Show wireless interfaces and info
iwlist wlan0 scan               # Scan for networks
iw wlan0 connect MyNetwork      # Connect to network (NL80211)

iwconfig (legacy)

iwconfig wlan0                  # Show wireless info
iwlist wlan0 scan               # Scan networks
iwconfig wlan0 essid MyNetwork  # Connect (legacy)

NetworkManager

Most desktop systems use NetworkManager for wireless:

nmcli device wifi list         # Scan networks
nmcli device wifi connect SSID password PASS
nmcli connection show           # List connections
nmcli radio wifi on            # Enable Wi-Fi

WPA Supplicant

WPA Supplicant (wpa_supplicant) handles WPA/WPA2/WPA3 authentication.

Configuration file /etc/wpa_supplicant/wpa_supplicant.conf:

ctrl_interface=DIR=/run/wpa_supplicant
update_config=1

network={
    ssid="MyNetwork"
    psk="password"
    key_mgmt=WPA-PSK
}

Connect:

wpa_supplicant -B -i wlan0 -c /etc/wpa_supplicant/wpa_supplicant.conf
dhclient wlan0

HostAPD

HostAPD turns a Linux machine into a wireless access point:

hostapd /etc/hostapd/hostapd.conf

Configuration:

interface=wlan0
driver=nl80211
ssid=MyAP
hw_mode=g
channel=6
wpa=2
wpa_passphrase=password
wpa_key_mgmt=WPA-PSK
rsn_pairwise=CCMP

Wireless Security

  • WEP: Broken, avoid entirely.
  • WPA: Vulnerable to dictionary attacks (TKIP).
  • WPA2: AES-CCMP, currently the minimum acceptable standard.
  • WPA3: SAE (Simultaneous Authentication of Equals) replaces PSK, resistant to dictionary attacks.
  • WPA3-Enterprise: 192-bit security mode for enterprise.

Regulatory Domain

Set the regulatory domain for legal compliance:

iw reg set US
iw reg get

Persist in /etc/default/crda:

REGDOMAIN=US