Command Line Wireless Tools on Linux
When you need check your wireless interface, you are able to use wireless tools. To know which tools you have installed on your operating system, just run the command
linux-7tpy:/home/poganin # compgen -abc -A function | grep iw
iwlist
iwgetid
iw
iwconfig
iwevent
iwpriv
iwspy
fliwheel
linux-7tpy:/home/poganin #
fliwheel has nothing to do with Wi-FI, so forget it.
Let’s start with iwconfig that displays current settings for wireless cards on your system. It’s a similar tool to ifconfig but used for Wi-Fi interfaces. It uses the statistics from /proc/net/wireless. In the beginning, it’s good to know the version:
linux-7tpy:/home/poganin # iwconfig –version
iwconfig Wireless-Tools version 30
Compatible with Wireless Extension v11 to v22.
Kernel Currently compiled with Wireless Extension v22.
wlan0 Recommend Wireless Extension v21 or later,
Currently compiled with Wireless Extension v22.
linux-7tpy:/home/poganin #
Wireless Extension (WE) are special extension for Linux kernels. Now, it’s not being under development because this idea is outdated but still used. In the man page for iwconfig, we can read.
“All these parameters and statistics are device dependent. Each driver
will provide only some of them depending on hardware support, and the
range of values may change. Please refer to the man page of each
device for details.”
So be aware that the output on your console may be different or even you will see nothing.
iwconfig
This shows and configures our wireless network interfaces.
Let’s start:
linux-7tpy:/home/poganin # iwconfig
wlan0 IEEE 802.11bg ESSID:”XXXXXXXXX”
Mode:Managed Frequency:2.412 GHz Access Point: XXXXXXXXXXXXX
Bit Rate=48 Mb/s Tx-Power=20 dBm
Retry long limit:7 RTS thr:off Fragment thr:off
Encryption key:on
Power Management:on
Link Quality=61/70 Signal level=-49 dBm
Rx invalid nwid:0 Rx invalid crypt:0 Rx invalid frag:0
Tx excessive retries:0 Invalid misc:1 Missed beacon:0
lo no wireless extensions.
eth0 no wireless extensions.
linux-7tpy:/home/poganin #
So the output shows us that we have one wireless interface, and there are two interfaces that aren’t wireless. We are interested in wlan0.
Also, we can run:
linux-7tpy:/home/poganin # iwconfig wlan0
wlan0 IEEE 802.11bg ESSID:”XXXXXXXXX”
Mode:Managed Frequency:2.412 GHz Access Point: XXXXXXXXXXXXX
Bit Rate=48 Mb/s Tx-Power=20 dBm
Retry long limit:7 RTS thr:off Fragment thr:off
Encryption key:on
Power Management:on
Link Quality=61/70 Signal level=-49 dBm
Rx invalid nwid:0 Rx invalid crypt:0 Rx invalid frag:0
Tx excessive retries:0 Invalid misc:1 Missed beacon:0
linux-7tpy:/home/poganin #
However, we have got no more information. To get more, just use other commands. With using iwconfig, we can not only show the information, but also manipulate them.Refer to the man page to get more info. The synopsis is:
iwconfig interface parameter value
For example:
iwconfig wlan0 mode Managed
With this command, we will set our wlan0 interface to manged mode. In other words, our computer connects to a network composed of many Access Points with roaming.
iwlist
This showing lists of parameters your wireless card supports.
linux-7tpy:/home/poganin # iwlist
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
linux-7tpy:/home/poganin #
So let’s use the scanning parameter:
linux-7tpy:/home/poganin # iwlist wlan0 scanning
wlan0 Scan completed :
Cell 01 – Address: XXXXXXXXXXXXXXXXX
Channel:1
Frequency:2.412 GHz (Channel 1)
Quality=58/70 Signal level=-52 dBm
Encryption key:on
ESSID:”XXXXXXXX”
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
Bit Rates:24 Mb/s; 36 Mb/s; 48 Mb/s; 54 Mb/s
Mode:Master
Extra:tsf=XXXXXXXXXXXXXXXX
Extra: Last beacon: 5056ms ago
IE: Unknown: XXXXXXXXXXXXXXXXXXXX
IE: Unknown: XXXXXXXXXXXXXXXXXXXX
IE: Unknown: XXXXXXXX
IE: Unknown: XXXXXXXX
IE: Unknown: XXXXXXXXXXXXXXXXXXXXXX
IE: WPA Version 1
Group Cipher : TKIP
Pairwise Ciphers (1) : TKIP
Authentication Suites (1) : PSK
IE: Unknown: XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
linux-7tpy:/home/poganin #
A lot of useful information.
iwspy
This shows us the quality-of-link information from specific nodes.
linux-7tpy:/home/poganin # iwspy
wlan0 Interface doesn’t support wireless statistic collection
lo Interface doesn’t support wireless statistic collection
eth0 Interface doesn’t support wireless statistic collection
linux-7tpy:/home/poganin #
Alas, we can’t get the information form our wireless interface. No support! but your interface can support that, so try it out.
iwpriv
This configures optionals (private) parameters of our wireless interface
linux-7tpy:/home/poganin # iwpriv
wlan0 no private ioctls.
lo no private ioctls.
eth0 no private ioctls.
linux-7tpy:/home/poganin #
Alas, we have no input/output control for our wireless interface because it’s an outdated tool and my openSuse is a modern operating system.
iwgetid
This shows ESSID, NWID or AP/Cell Address of our wireless network
linux-7tpy:/home/poganin # iwgetid
wlan0 ESSID:”XXXXXXXX”
linux-7tpy:/home/poganin #
iwevent
Display Wireless Events generated by drivers and setting changes.
linux-7tpy:/home/poganin # iwevent
Waiting for Wireless Events from interfaces…
14:47:02.119793 wlan0 Scan request completed
14:49:02.123418 wlan0 Scan request completed
^C
linux-7tpy:/home/poganin #
We can see all events. In this case, we got two evens Scan request completed. They are the results of the scan because of running iwlist (iwlist wlan0 scanning).
We can interrupt the command by using Ctrl+C.
At the end, we can also check the /proc/net/wireless file.
linux-7tpy:/home/poganin # cat /proc/net/wireless
Inter- | sta- | Quality | Discarded packets | Missed | WE
face | tus | link level noise | nwid crypt frag retry misc | beacon | 22
wlan0: 0000 65. -45. -256 0 0 0 0 2 0
linux-7tpy:/home/poganin #
Many details.
Tomasz Zackiewicz 