Posts Tagged ‘iwconfig’

Change Linux Wireless Access Point connection from text terminal with iwconfig

Monday, October 8th, 2018

wireless-change-wireless-network-to-connect-to-using-console

If you have configured a couple of Wireless connections at home or work on your Laptop  and each of the remote Wi-FI access points are at different distance (some APs are situated at closer range than others) and your Linux OS keeps connecting sometimes to the wrong AP by default you'll perhaps want to change that behavior, so you keep connected to the Wi-Fi AP that has the best Link Quality (is situatated physically at closest location to your laptop integrated wifi card).
Using a Graphical tool such as Gnome Network Manager / Wicd Network Manager or KDE's Network Manager is great and easy way to do it but sometimes if you do upgrade of your GNU / Linux and the upgrade fails and your Graphical Environment GNOME / KDE / OpenBox / Window Maker or whatever Window Manager you use fails to start it is super handy to use text console (terminal) to connect to the right wiki in order to do a deb / rpm package rollback to revert your GUI environment or Xorg to the older working release.

Connection to WPA or WEP protected APs on GNU / Linux on a low level is done by /sbin/iwlist , /sbin/iwconfig and wpa_supplicant

wpasupplicant and network-manager (if you're running Xorg server).

 

/sbin/iwlist scan
 

 

wlp3s0    Scan completed :
          Cell 01 – Address: 10:FE:ED:43:CB:0E
                    Channel:6
                    Frequency:2.437 GHz (Channel 6)
                    Quality=64/70  Signal level=-46 dBm  
                    Encryption key:on
                    ESSID:"Magdanoz"
                    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=00000032cff7c214
                    Extra: Last beacon: 144ms ago
                    IE: Unknown: 00084D616764616E6F7A
                    IE: Unknown: 010882848B960C121824
                    IE: Unknown: 030106
                    IE: Unknown: 0706555320010B1B
                    IE: Unknown: 2A0100
                    IE: IEEE 802.11i/WPA2 Version 1
                        Group Cipher : TKIP
                        Pairwise Ciphers (2) : CCMP TKIP
                        Authentication Suites (1) : PSK
                    IE: Unknown: 32043048606C

 

iwlist command is used to get more detailed wireless info from a wireless interface (in terminal this command shows you the wifi networks available to connect to and various info such as the type of Wifi network the Wifi Name / network quality Frequency (is it it spreading the wifi signal at 2.4 Ghz or 5 Ghz frequency) etc.

 

# ifconfig interafce_name down

 

For example on my Thinkpad the wifi interface is wlp3s0 to check what is yours do ifconfig -a e.g.

 

root@jeremiah:~# /sbin/ifconfig -a
enp0s25: flags=4099<UP,BROADCAST,MULTICAST>  mtu 1500
        ether 00:21:cc:cc:b2:27  txqueuelen 1000  (Ethernet)
        RX packets 0  bytes 0 (0.0 B)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 0  bytes 0 (0.0 B)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0
        device interrupt 20  memory 0xf3900000-f3920000  

 

lo: flags=73<UP,LOOPBACK,RUNNING>  mtu 65536
        inet 127.0.0.1  netmask 255.0.0.0
        inet6 ::1  prefixlen 128  scopeid 0x10<host>
        loop  txqueuelen 1  (Local Loopback)
        RX packets 350  bytes 28408 (27.7 KiB)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 350  bytes 28408 (27.7 KiB)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

wlp3s0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
        inet 192.168.0.103  netmask 255.255.255.0  broadcast 192.168.0.255
        inet6 fe80::6267:20ff:fe3c:20ec  prefixlen 64  scopeid 0x20<link>
        ether 60:67:20:3c:20:ec  txqueuelen 1000  (Ethernet)
        RX packets 299735  bytes 362561115 (345.7 MiB)
        RX errors 0  dropped 1  overruns 0  frame 0
        TX packets 278518  bytes 96996135 (92.5 MiB)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

 

Next use iwconfig on Debian / Ubuntu Linux it is part of wireless-tools deb package.

 

root@jeremiah:~# /sbin/iwconfig interface essid "Your-Acess-Point-name"

 

To check whether you're connected to a wireless network you can do:

http://pc-freak.net/images/check-wireless-frequency-access-point-mac-and-wireless-name-iwconfig-linux

root@jeremiah:~# iwconfig
enp0s25   no wireless extensions.

 

lo        no wireless extensions.

wlp3s0    IEEE 802.11  ESSID:"Magdanoz"  
          Mode:Managed  Frequency:2.437 GHz  Access Point: 10:FE:ED:43:CB:0E   
          Bit Rate=150 Mb/s   Tx-Power=15 dBm   
          Retry short limit:7   RTS thr:off   Fragment thr:off
          Encryption key:off
          Power Management:off
          Link Quality=61/70  Signal level=-49 dBm  
          Rx invalid nwid:0  Rx invalid crypt:0  Rx invalid frag:0
          Tx excessive retries:5  Invalid misc:1803   Missed beacon:0


N.B. ! To get a list of all your PC network interfaces you can use cmd:

 

root@jeremiah:/home/hipo# ls -al /sys/class/net/
total 0
drwxr-xr-x  2 root root 0 Oct  8 22:53 .
drwxr-xr-x 52 root root 0 Oct  8 22:53 ..
lrwxrwxrwx  1 root root 0 Oct  8 22:53 enp0s25 -> ../../devices/pci0000:00/0000:00:19.0/net/enp0s25
lrwxrwxrwx  1 root root 0 Oct  8 22:53 lo -> ../../devices/virtual/net/lo
lrwxrwxrwx  1 root root 0 Oct  8 22:53 wlp3s0 -> ../../devices/pci0000:00/0000:00:1c.1/0000:03:00.0/net/wlp3s0

show-all-network-interfaces-with-netstat-linux

or use netstat like so:

root@jeremiah:/home/hipo# netstat -i | column -t
Kernel   Interface  table
Iface    MTU        RX-OK   RX-ERR  RX-DRP  RX-OVR  TX-OK   TX-ERR  TX-DRP  TX-OVR  Flg
enp0s25  1500       0       0       0       0       0       0       0       0       BMU
lo       65536      590     0       0       0       590     0       0       0       LRU
wlp3s0   1500       428112  0       1       0       423538  0       0       0       BMRU

 


To get only the Wireless network card interface on Linux (e.g. find out which of the listed above interfaces is your wireless adapter's name), use iw command (that shows devices and their configuration):

 

root@jeremiah:/home/hipo# iw dev
phy#0
    Interface wlp3s0
        ifindex 3
        wdev 0x1
        addr 60:67:20:3c:20:ec
        type managed
        channel 6 (2437 MHz), width: 40 MHz, center1: 2427 MHz
        txpower 15.00 dBm

 

linux-wireless-terminal-console-check-wireless-interfaces-command

  • If you need to get only the active Wireless adapter device assigned by Linux kernel

 

root@jeremiah:~# iw dev | awk '$1=="Interface"{print $2}'

 

To check the IP / Netmask and Broadcase address assigned by connected Access Point use ifconfig
with your Laptop Wireless Interface Name.

show-extra-information-ip-netmask-broadcast-about-wireless-interface-linux

root@jeremiah:~# /sbin/ifconfig wlp3s0
wlp3s0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
        inet 192.168.0.103  netmask 255.255.255.0  broadcast 192.168.0.255
        inet6 fe80::6267:20ff:fe3c:20ec  prefixlen 64  scopeid 0x20<link>
        ether 60:67:20:3c:20:ec  txqueuelen 1000  (Ethernet)
        RX packets 319534  bytes 365527097 (348.5 MiB)
        RX errors 0  dropped 1  overruns 0  frame 0
        TX packets 285464  bytes 99082701 (94.4 MiB)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0


As you can see in above 3 examples iwconfig could configure various settings regarding the wireless network interface.

It is really annoying because sometimes if you have configured your Linux to connect to multiple access points, the wifi adapter might keep connecting to an access point that is more distanced from you and because of that the Bandwidth might be slower and that could impact your Internet connectivity, to fix that and get rid of any networks that are automatically set to connect to that you don't want to, just delete the correspodning files (the Wifi file name coincides with the Wireless AP network name).
All stored Wi-FI access points that your Linux is configured to connect to are stored inside /etc/NetworkManager/system-connections/

For example to delete an auto connection to wireless router with a name NetGear do:

 

root@jeremiah:~# rm -f /etc/NetworkManager/system-connections/NetGear

 

For a complete list of stored Wifi Networks that your PC might connect (and authorize to if configured so) do:

 

root@jeremiah:~# ls -a /etc/NetworkManager/system-connections/
Magdanoz
NetGear

LinkSys
Cobra
NetIs
WirelessNet

 

After deleting the required Networks you want your computer to not automatically connect to to make NetworkManager aware of that restart it with:
 

hipo@jeremiah:~# systemctl restart NetworkManager.service


or if you hate systemd like I do just use the good old init script to restart:

 

hipo@jeremiah:~# /etc/init.d/network-manager restart


To get some more informatoin on the exact network you're connected, you can run:

show-information-about-wireless-connection-on-gnu-linux

 

hipo@jeremiah:~# systemctl status NetworkManager.service
● NetworkManager.service – Network Manager
   Loaded: loaded (/lib/systemd/system/NetworkManager.service; enabled; vendor preset: enabled)
   Active: active (running) since Mon 2018-10-08 22:35:09 EEST; 15s ago
     Docs: man:NetworkManager(8)
 Main PID: 13721 (NetworkManager)
    Tasks: 5 (limit: 4915)
   CGroup: /system.slice/NetworkManager.service
           ├─13721 /usr/sbin/NetworkManager –no-daemon
           └─13742 /sbin/dhclient -d -q -sf /usr/lib/NetworkManager/nm-dhcp-helper -pf /var/run/dhclient-wlp3s0.pid -lf /var/lib/NetworkManager/dhclie

 

Oct 08 22:35:15 jeremiah NetworkManager[13721]:   [1539027315.6657] dhcp4 (wlp3s0): state changed unknown -> bound
Oct 08 22:35:15 jeremiah dhclient[13742]: bound to 192.168.0.103 — renewal in 2951 seconds.
Oct 08 22:35:15 jeremiah NetworkManager[13721]:
  [1539027315.6735] device (wlp3s0): state change: ip-config -> ip-check (reason 'none') [70 80
Oct 08 22:35:15 jeremiah NetworkManager[13721]:
  [1539027315.6744] device (wlp3s0): state change: ip-check -> secondaries (reason 'none') [80 9
Oct 08 22:35:15 jeremiah NetworkManager[13721]:
  [1539027315.6747] device (wlp3s0): state change: secondaries -> activated (reason 'none') [90
Oct 08 22:35:15 jeremiah NetworkManager[13721]:
  [1539027315.6749] manager: NetworkManager state is now CONNECTED_LOCAL
Oct 08 22:35:15 jeremiah NetworkManager[13721]:
  [1539027315.6812] manager: NetworkManager state is now CONNECTED_GLOBAL
Oct 08 22:35:15 jeremiah NetworkManager[13721]:
  [1539027315.6813] policy: set 'Magdanoz' (wlp3s0) as default for IPv4 routing and DNS
Oct 08 22:35:15 jeremiah NetworkManager[13721]:
  [1539027315.6816] device (wlp3s0): Activation: successful, device activated.
Oct 08 22:35:15 jeremiah NetworkManager[13721]:
  [1539027315.6823] manager: startup complete

 

How to install Toshiba Satellite L40 B14 Wireless Adapter ( ID 0bda:8197 Realtek Semiconductor Corp. RTL8187B) on Ubuntu and Debian Linux

Thursday, April 28th, 2011

http://pc-freak.net/images/toshiba-satellite-l40

How to install Toshiba L40 B14 Wireless Adapter ( ID 0bda:8197 Realtek Semiconductor Corp. RTL8187B) on Ubuntu and Debian Linux
I've been struggling for more than 10 hours to fix up issues on a Ubuntu Maverick-Meerkaat with a rtl8187B Wireless Adapter

The RTL8187B almost drove me mad. I could see the wlan0 which meant the kernel is detecting the device, I could even bring it up with ifconfig wlan0 up , however when I tried it in gnome's network-manager or wicd the wireless networks were not showing up.

Trying to scan for networks using the commands:


ubuntu:~# iwlist wlan0 scan

was also unsuccesful, trying to bring up and down the wireless wlan0 interface with:


ubuntu:~# iwconfig wlan0 up

or


ubuntu:~# iwconfig wlan0 down

Both returned the error:
iwconfig: unknown command "up" and iwconfig: unknown command "down"

Running simply iwconfig was properly returning information about my Wireless Interface wlan0 :


wlan0 IEEE 802.11bg ESSID:off/any
Mode:Managed Access Point: Not-Associated Tx-Power=20 dBm
Retry long limit:7 RTS thr:off Fragment thr:off
Encryption key:off
Power Management:off

The exact information I could get about the wireless device was via the command:


ubuntu:~# lsusb | grep realtek
Bus 001 Device 002: ID 0bda:8197 Realtek Semiconductor Corp. RTL8187B Wireless Adapter

Trying manually to scan for wireless networks from console or gnome-terminal with command returned also the below weird results:


ubuntu:~# iwconfig wlan0 scan
iwconfig: unknown command "scan"

More oddly tunning wlan0 interface with commands like:


ubuntu:~# iwconfig wlan0 mode managed
ubuntu:~# iwconfig wlan0 essid ESSID
ubuntu:~# iwconfig wlan0 rate 11M

were succesful …

I read a bunch of documentation online concerning the wireless card troubles on Ubuntu, Gentoo, Debian etc.

Just few of all the resources I've read and tried are:

http://rtl-wifi.sourceforge.net/wiki/Main_Page (Returning empty page already a lot resource)
http://rtl8187b.sourceforge.net (A fork of rtl-wifi.sourceforge.net which is still available though it was not usable)

Some of the other resources which most of the people recommended as a way to properly install the RTL8187B wireless driver on linux was located on the website:

http://datanorth.net/~cuervo/rtl8187b/ (Trying to access this page returned a 404 error e.g. this page is no-longer usable)

I found even a webpage in Ubuntu Help which claimed to explain how to properly install and configure the RTL8187B wireless driver on which is below:

https://help.ubuntu.com/community/WifiDocs/Device/RealtekRTL8187b

Even the Ubuntu help instructions were pointing me to the broken cuervo's website URL

Anyways I was able to find the rtl8187b-modified-dist.tar.gz online and made a mirror of rtl8187b-modified-dist.tar.gz which you can download here

Another rtl8187b driver I found was on a toshiba website made especailly for the wireless linux drivers:

http://linux.toshiba-dme.co.jp/linux/eng/pc/sat_PSPD0_report.htm

The questionable file which was claimed to properly be able to make the Realtek Semiconductor Corp. RTL8187B Wireless Adapter to work out was called rl8187b-modified-804.tar.gz.
I've made a mirror of rtl8187b-modified-804.tar.gz is here

None of the driver archives rtl8187b-modified-dist.tar.gz and rl8187b-modified-804.tar.gz that was supposed to make the Toshiba L40 realtek wireless to work out, after compiling and installing the drivers from source worked out …

Both archives produced plenty of error messages and it seems on newer kernels like the one on this notebook:

Linux zlatina 2.6.35-28-generic #50-Ubuntu SMP Fri Mar 18 19:00:26 UTC 2011 i686 GNU/Linux, they're no longer usable.

The compile errors I got when I tried compiling the rtl8187b driver provided by the archive rtl8187b-modified-dist were:


root@ubuntu:/home/zlatina/rtl8187b-modified# sh makedrv
rm -fr *.mod.c *.mod *.o .*.cmd *.mod.* *.ko *.o *~
make -C /lib/modules/2.6.35-28-generic/build M=/home/zlatina/rtl8187b-modified/ieee80211 CC=gcc modules
make[1]: Entering directory `/usr/src/linux-headers-2.6.35-28-generic'
scripts/Makefile.build:49: *** CFLAGS was changed in "/home/zlatina/rtl8187b-modified/ieee80211/Makefile". Fix it to use EXTRA_CFLAGS. Stop.
make[1]: *** [_module_/home/zlatina/rtl8187b-modified/ieee80211] Error 2
make[1]: Leaving directory `/usr/src/linux-headers-2.6.35-28-generic'
make: *** [modules] Error 2
rm -fr *.mod.c *.mod *.o .*.cmd *.ko *~
make -C /lib/modules/2.6.35-28-generic/build M=/home/zlatina/rtl8187b-modified/rtl8187 CC=gcc modules
make[1]: Entering directory `/usr/src/linux-headers-2.6.35-28-generic'
scripts/Makefile.build:49: *** CFLAGS was changed in "/home/zlatina/rtl8187b-modified/rtl8187/Makefile". Fix it to use EXTRA_CFLAGS. Stop.
make[1]: *** [_module_/home/zlatina/rtl8187b-modified/rtl8187] Error 2
make[1]: Leaving directory `/usr/src/linux-headers-2.6.35-28-generic'
make: *** [modules] Error 2
root@ubuntu:/home/zlatina/rtl8187b-modified#

Another driver I tried which was found on aircrack-ng.org's website was rtl8187_linux_26.1010.zip

Here are the error messages I experienced while I tried to compile the realtek wireless driver from the archive rtl8187_linux_26.1010.0622.2006


compilation terminated.
make[2]: *** [/home/zlatina/rtl8187_linux_26.1010.0622.2006/beta-8187/r8187_core.o] Error 1
make[1]: *** [_module_/home/zlatina/rtl8187_linux_26.1010.0622.2006/beta-8187] Error 2
make[1]: Leaving directory `/usr/src/linux-headers-2.6.35-28-generic'
make: *** [modules] Error 2
make: *** [modules] Error 2

I tried a number of fix ups hoping to solve the compile error messages, but my efforts were useless, as it seems many things has changed in newer Ubuntu versions and they could no longer be compiled.

As I realized I couldn't make the native drivers provided by the above sources compile, I decided to give a try to the Windows drivers for Realtek 8187B with ndiswrapper, a link for download of Realtek 8187B (RTL8187B_XP_6.1163.0331.2010_Win7_62.1182.0331.2010_UI_1.00.0179 is found here

I untarred the
RTL8187B_XP driver
and used ndiswrapper to load driver like so:


root@ubuntu:~# tar -zxvf
RTL8187B_XP_6.1163.0331.2010_Win7_....L.tar.gz
root@ubuntu:/home/zlatina/RTL8187B#
root@ubuntu:/home/zlatina/RTL8187B# cd Driver/WinXP
root@ubuntu:/home/zlatina/RTL8187B/Driver/WinXP# ndiswrapper -i net8187b.inf

In order to test the RTL8178B Windows driver I used:


root@ubuntu:~# ndiswrapper -l
net8187b : driver installed
device (0BDA:8197) present (alternate driver: rtl8187)

To finally load the Windows XP RTL8187B driver on the Ubuntu I used again ndiswrapper:


root@ubuntu:~# ndiswrapper -m

Further on I used the ndisgtk graphical ndiswrapper interface to once again test if the Windows driver is working on the Ubuntu and it seemed like it is working, however still my wicd was unable to find any wireless network ….

There were many online documentation which claimed that the driver for rtl8187b works out of the box on newer kernel releases (kernel versions > 2.6.24)

Finally I found out there is a driver which is a default one with the Ubuntu e.g. rtl8187.ko , I proceeded and loaded the module:


root@ubuntu:~# modprobe rtl8187

I also decided to check out if the hardware switch button of the Toshiba Satellite L40 notebook is not switched off and guess what ?! The Wireless ON/OFF button was switched OFF!!! OMG …

I switched on the button and wicd immediately started showing up the wireless networks …

To make the rtl8187 module load on Ubuntu boot up, I had to issue the command:


root@ubuntu:~# echo 'rtl8187' >> /etc/modules

Voila after all this struggle the wireless card is working now, it's sad I had to loose about 10 hours of time until I come with the simple solution of using the default provided ubuntu driver rtl8187 , what is strange is how comes that it does not load up automatically.

Thanks God it works now.