iwconfig, iwlist and iwgetid

iwconfig is to Wi-Fi what ifconfig is to Ethernet: the classic Linux tool, still in a thousand tutorials, no longer installed by default and unable to handle anything newer than WEP. This page explains its output, then shows what to type instead.

Status

wireless-tools (iwconfig, iwlist, iwgetid, iwspy, iwpriv, iwevent) was written by Jean Tourrilhes at HP for the Wireless Extensions kernel API of the late 1990s. That API was frozen around 2008 and replaced by nl80211/cfg80211, driven by the iw command. Modern drivers still emulate the old API for compatibility, which is why iwconfig mostly works when installed, but:

• It cannot configure WPA or WPA2/WPA3 at all; only open networks and WEP. Connecting to any real network needs wpa_supplicant, nmcli or iwctl.
• It knows nothing about 802.11n/ac/ax features, 6 GHz, mesh, P2P or multiple virtual interfaces.
• Some drivers report zeros or nonsense through the compatibility layer.
• Ubuntu, Debian, Fedora and Arch no longer install it by default; the package is wireless-tools.

For seeing what you are connected to and how strong the signal is, it still works and is quick to read.

Reading iwconfig output

iwconfig
iwconfig wlan0

wlan0     IEEE 802.11  ESSID:"HomeWiFi"
          Mode:Managed  Frequency:5.22 GHz  Access Point: D4:6E:0E:11:22:34
          Bit Rate=866.7 Mb/s   Tx-Power=22 dBm
          Retry short limit:7   RTS thr:off   Fragment thr:off
          Power Management:on
          Link Quality=60/70  Signal level=-50 dBm
          Rx invalid nwid:0  Rx invalid crypt:0  Rx invalid frag:0
          Tx excessive retries:0  Invalid misc:12   Missed beacon:0

eth0      no wireless extensions.

lo        no wireless extensions.

IEEE 802.11

The protocol family. Older output shows the letter (802.11abgn); newer drivers just say 802.11.

ESSID:"HomeWiFi"

The network name you are associated with. ESSID:off/any means not associated.

Mode:Managed

A normal client. Other modes: Master (access point), Ad-Hoc, Monitor (packet capture), Repeater, Secondary, Auto.

Frequency:5.22 GHz

The channel's centre frequency. 5.22 GHz is channel 44; 2.437 GHz is channel 6. Formula: 5 GHz channel = (MHz − 5000) / 5; 2.4 GHz channel = (MHz − 2407) / 5.

Access Point: D4:6E:0E:11:22:34

The BSSID, the MAC of the access point you are on. Not-Associated when disconnected.

Bit Rate=866.7 Mb/s

Current negotiated PHY rate, not throughput. Expect real transfers at roughly half.

Tx-Power=22 dBm

Transmit power. 20 dBm is the usual EU limit on 2.4 GHz; 23 dBm on some 5 GHz bands.

Power Management:on

The card sleeps between beacons. Saves battery, adds latency; a common cause of laggy SSH sessions over Wi-Fi.

Link Quality=60/70

A driver-specific figure; for most Intel and Atheros drivers it is derived from signal level and 70 is the maximum.

Signal level=-50 dBm

Received signal strength. −30 to −50 excellent, −50 to −67 good, −67 to −75 fair, below −75 poor. Some drivers show a percentage or an arbitrary scale instead.

Rx invalid nwid / crypt / frag

Frames received from other networks on the same channel, frames the card could not decrypt, and fragments it could not reassemble. Counting up steadily with poor throughput suggests channel congestion.

Tx excessive retries / Missed beacon

Retries indicate interference or weak signal; missed beacons mean the AP's periodic announcements are not being heard, which precedes a disconnect.

no wireless extensions.

Not a wireless interface. Normal for eth0 and lo.

iwconfig settings (rarely appropriate today)

sudo iwconfig wlan0 essid "OpenCafe"          # associate with an OPEN network (no WPA support)
sudo iwconfig wlan0 essid any
sudo iwconfig wlan0 mode Managed
sudo iwconfig wlan0 mode Monitor                # capture mode; use 'iw dev wlan0 set type monitor' instead
sudo iwconfig wlan0 channel 6
sudo iwconfig wlan0 freq 5.22G
sudo iwconfig wlan0 ap D4:6E:0E:11:22:34         # pin to one BSSID
sudo iwconfig wlan0 rate 54M
sudo iwconfig wlan0 rate auto
sudo iwconfig wlan0 txpower 15
sudo iwconfig wlan0 power off                   # disable power saving
sudo iwconfig wlan0 power on
sudo iwconfig wlan0 key s:abcde                 # WEP only; obsolete and insecure
sudo iwconfig wlan0 key off
sudo iwconfig wlan0 rts 2347
sudo iwconfig wlan0 frag 2346
sudo iwconfig wlan0 nick "laptop"

On a machine running NetworkManager, most of these are undone within seconds when NM reasserts its profile. Use the NetworkManager or iw equivalents below.

iwlist

sudo iwlist wlan0 scan                          # every network in range (root for a fresh scan)
sudo iwlist wlan0 scan | grep -E 'ESSID|Quality|Channel|Encryption'
iwlist wlan0 scan last                          # cached results without rescanning
iwlist wlan0 channel                            # channels/frequencies the card supports
iwlist wlan0 rate                               # supported bit rates
iwlist wlan0 txpower
iwlist wlan0 power
iwlist wlan0 encryption                         # WEP key sizes only
iwlist wlan0 event                              # wireless events the driver can report

wlan0     Scan completed :
          Cell 01 - Address: D4:6E:0E:11:22:34
                    Channel:44
                    Frequency:5.22 GHz (Channel 44)
                    Quality=60/70  Signal level=-50 dBm
                    Encryption key:on
                    ESSID:"HomeWiFi"
                    Bit Rates:6 Mb/s; 9 Mb/s; 12 Mb/s; 18 Mb/s; 24 Mb/s; 36 Mb/s
                              48 Mb/s; 54 Mb/s
                    Mode:Master
                    Extra:tsf=0000004a2b1c3d4e
                    Extra: Last beacon: 120ms ago
                    IE: IEEE 802.11i/WPA2 Version 1
                        Group Cipher : CCMP
                        Pairwise Ciphers (1) : CCMP
                        Authentication Suites (1) : PSK
          Cell 02 - Address: 3C:22:FB:AA:BB:CC
                    Channel:1
                    ...

Encryption key:on with an IE: IEEE 802.11i/WPA2 block means WPA2; Encryption key:on with no IE means WEP; Encryption key:off is an open network. iwlist shows WPA3 as WPA2 with an unfamiliar authentication suite, because it predates it.

iwgetid

The script-friendly one: prints just one value with no decoration.

iwgetid                # wlan0     ESSID:"HomeWiFi"
iwgetid -r             # HomeWiFi          (raw: just the name)
iwgetid -a -r          # D4:6E:0E:11:22:34 (access point MAC)
iwgetid -c -r          # 44                (channel)
iwgetid -f -r          # 5.22e+09          (frequency in Hz)
iwgetid -m -r          # Managed           (mode)
iwgetid -p -r          # 1                 (protocol)

The rest of the family

iwconfig to iw and nmcli

The full modern reference is on the Wi-Fi from the command line page.

Installing

sudo apt install wireless-tools       # Debian, Ubuntu
sudo dnf install wireless-tools       # Fedora
sudo pacman -S wireless_tools         # Arch (note the underscore)
sudo apk add wireless-tools           # Alpine
# iw (recommended instead)
sudo apt install iw  /  sudo dnf install iw  /  sudo pacman -S iw

Common errors

Related pages

• Wi-Fi from the command line (iw, nmcli, netsh wlan, wdutil)
• ifconfig, its wired sibling
• iw on the Linux tools page