Jul 162008
 


iwlist command in Linux is used to extract more detailed information from a Wireless Network interface which may not be available from running the iwconfig command. This includes detailed information on available Wireless networks, Frequencies supported, power management support, Encryption key sizes supported, WPA keys configured on the device etc.

The general syntax is

iwlist <interface> <category>

If no interface is specified, it will display information on all interfaces available on the system

Simply,type iwlist or iwlist –help to find a detailed list.

opensuse11:~ # iwlist

or

opensuse11:~ # iwlist –help
Usage: iwlist [interface] scanning [essid NNN] [last]
[interface] frequency
[interface] channel
[interface] bitrate
[interface] rate
[interface] encryption
[interface] keys
[interface] power
[interface] txpower
[interface] retry
[interface] ap
[interface] accesspoints
[interface] peers
[interface] event
[interface] auth
[interface] wpakeys
[interface] genie
[interface] modulation

Scanning
The most used option is the “scanning” which scans for all available access points, ad-hoc wireless devices etc within the range with detailed information which depends on the cards capabilities.
My Intel 3945 picked up as many as 10 Wireless networks within range and I need to cutdown on the list

opensuse11:~ # iwlist wlan0 scan
wlan0     Scan completed :
Cell 01 – Address: 00:xx:xx:xx:xx:xx
ESSID:”Live1″
Mode:Master
Channel:1
Frequency:2.412 GHz (Channel 1)
Quality=46/100  Signal level:-81 dBm  Noise level=-69 dBm
Encryption key:on
IE: WPA Version 1
Group Cipher : TKIP
Pairwise Ciphers (1) : TKIP
Authentication Suites (1) : PSK
Bit Rates:1 Mb/s; 2 Mb/s; 5.5 Mb/s; 11 Mb/s; 18 Mb/s
24 Mb/s; 36 Mb/s; 54 Mb/s; 6 Mb/s; 9 Mb/s
12 Mb/s; 48 Mb/s
Extra:tsf=000000155fac7185
Extra: Last beacon: 3268ms ago
Cell 02 – Address: 01:xx:xx:xx:xx:xx
ESSID:”SKYNET”
Mode:Master
Channel:6
Frequency:2.437 GHz (Channel 6)
Quality=94/100  Signal level:-35 dBm  Noise level=-69 dBm
Encryption key:on
IE: WPA Version 1
Group Cipher : TKIP
Pairwise Ciphers (1) : TKIP
Authentication Suites (1) : PSK
Bit Rates:1 Mb/s; 2 Mb/s; 5.5 Mb/s; 11 Mb/s; 6 Mb/s
9 Mb/s; 12 Mb/s; 18 Mb/s; 24 Mb/s; 36 Mb/s
48 Mb/s; 54 Mb/s
Extra:tsf=00000001779b1581
Extra: Last beacon: 4ms ago

Display Channels/Frequencies

To display the channels and frequencies supported by the device

opensuse11:~ # iwlist wlan0 channel

or

opensuse11:~ # iwlist wlan0 frequency
wlan0     19 channels in total; available frequencies :
Channel 01 : 2.412 GHz
Channel 02 : 2.417 GHz
Channel 03 : 2.422 GHz
Channel 04 : 2.427 GHz
Channel 05 : 2.432 GHz
Channel 06 : 2.437 GHz
Channel 07 : 2.442 GHz
Channel 08 : 2.447 GHz
Channel 09 : 2.452 GHz
Channel 10 : 2.457 GHz
Channel 11 : 2.462 GHz
Channel 36 : 5.18 GHz
Channel 40 : 5.2 GHz
Channel 44 : 5.22 GHz
Channel 48 : 5.24 GHz
Channel 52 : 5.26 GHz
Channel 56 : 5.28 GHz
Channel 60 : 5.3 GHz
Channel 64 : 5.32 GHz
Current Frequency:2.437 GHz (Channel 6)

Display Bit Rates supported

opensuse11:~ # iwlist wlan0 rate

or

opensuse11:~ # iwlist wlan0 bitrate
wlan0     unknown bit-rate information.
Current Bit Rate:54 Mb/s

Display Encryption Key Sizes and Keys set

opensuse11:~ # iwlist wlan0 keys

or

opensuse11:~ # iwlist wlan0 encryption
wlan0     2 key sizes : 40, 104bits
4 keys available :
[1]: off
[2]: xxxx-xxxx-xxxx-xxxx-xxxx-xxxx-xxxx-xxxx-xxxx-xxxx-xxxx-xxxx-xxxx-xxxx-xxxx-xxxx (256 bits)
[3]: yyyy-yyyy-yyyy-yyyy-yyyy-yyyy-yyyy-yyyy-yyyy-yyyy-yyyy-yyyy-yyyy-yyyy-yyyy-yyyy (256 bits)
[4]: off
Current Transmit Key: [2]
Security mode:open

Display Power Management options

opensuse11:~ # iwlist wlan0 power
wlan0     Current mode:off

Display Transmit Power available

opensuse11:~ # iwlist wlan0 txpower
wlan0     unknown transmit-power information.

Current Tx-Power=15 dBm       (31 mW)

Display Retry Transmit/Lifetime on device

opensuse11:~ # iwlist wlan0 retry
wlan0     Fixed limit    ;  min limit:0
max limit:255
Current mode:on
min limit:7
max limit:4

Display Wireless Events supported

opensuse11:~ # iwlist wlan0 events
wlan0     Wireless Events supported :
0x8B04 : Set Frequency/Channel (kernel generated)
0x8B06 : Set Mode (kernel generated)
0x8B15 : New Access Point/Cell address – roaming
0x8B19 : Scan request completed
0x8B1A : Set ESSID (kernel generated)
0x8B2A : Set Encoding (kernel generated)

Display WPA Authentication parameters

opensuse11:~ # iwlist wlan0 auth
wlan0     Authentication capabilities :
WPA
WPA2
CIPHER-TKIP
CIPHER-CCMP
Current Authentication algorithm :
open

Display Encryption Keys set

opensuse11:~ # iwlist wlan0 wpa
wlan0     2 key sizes : 40, 104bits
4 keys available :
Error reading wpa keys (SIOCGIWENCODEEXT): Operation not supported

Display Generic Informartion Elements (WPA)

opensuse11:~ # iwlist wlan0 genie
wlan0     no generic IE (Operation not supported).

Display supported Modulations

opensuse11:~ # iwlist wlan0 modulation
wlan0     unknown modulation information.