Difference between revisions of "Wireless network configuration"

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{{Related articles start}}
{{Related|Network Configuration}}
{{Related|Software Access Point}}
{{Related|Ad-hoc networking}}
{{Related|Internet Sharing}}
{{Related articles end}}
Configuring wireless is a two-part process; the first part is to identify and ensure the correct driver for your wireless device is installed (they are available on the installation media, but often have to be installed explicitly), and to configure the interface. The second is choosing a method of managing wireless connections. This article covers both parts, and provides additional links to wireless management tools.
== Device driver ==
The default Arch Linux kernel is ''modular'', meaning many of the drivers for machine hardware reside on the hard drive and are available as [[Kernel modules|modules]]. At boot, [[udev]] takes an inventory of your hardware and loads appropriate modules (drivers) for your corresponding hardware, which will in turn allow creation of a network ''interface''.
Some wireless chipsets also require firmware, in addition to a corresponding driver. Many firmware images are provided by the {{Pkg|linux-firmware}} package which is installed by default, however, proprietary firmware images are not included and have to be installed separately. This is described in [[#Installing driver/firmware]].
* Udev is not perfect. If the proper module is not loaded by udev on boot, simply [[Kernel modules#Loading|load it manually]]. Note also that udev may occasionally load more than one driver for a device, and the resulting conflict will prevent successful configuration. Make sure to [[Kernel modules#Blacklisting|blacklist]] the unwanted module.
* The interface name for different drivers and chipsets will vary. Some examples are {{ic|wlan0}}, {{ic|eth1}}, and {{ic|ath0}}. See also [[Network Configuration#Device names]].
{{Tip|Though not strictly required, it's a good idea to first install user-space tools mentioned in [[#Manual setup]], especially when some problem should appear.}}
=== Check the driver status ===
To check if the driver for your card has been loaded, check the output of {{ic|lspci -k}} command. You should see that some kernel driver is in use, for example:
{{hc|$ lspci -k|<nowiki>
06:00.0 Network controller: Intel Corporation WiFi Link 5100
Subsystem: Intel Corporation WiFi Link 5100 AGN
Kernel driver in use: iwlwifi
Kernel modules: iwlwifi
{{Note|The internal Wi-Fi card in some laptops may actually be a USB device, so you should check these commands too:
* {{ic|lsusb -v}}
* {{ic|<nowiki>dmesg | grep usbcore</nowiki>}}, you should see something like {{ic|usbcore: registered new interface driver rtl8187}} in the output
Also check the output of {{ic|ip link}} command to see if a wireless interface (e.g. {{ic|wlan0}}, {{ic|wlp2s1}}, {{ic|ath0}}) was created. Then bring the interface up with {{ic|ip link set ''interface'' up}}. For example, assuming the interface is {{ic|wlan0}}:
# ip link set wlan0 up
If you get this error message: {{ic|SIOCSIFFLAGS: No such file or directory}}, it most certainly means that your wireless chipset requires a firmware to function.
Check kernel messages for firmware being loaded:
{{hc|$ dmesg <nowiki>|</nowiki> grep firmware|<nowiki>
[  7.148259] iwlwifi 0000:02:00.0: loaded firmware version build 35138 op_mode iwldvm
If there is no relevant output, check the messages for the full output for the module you identified earlier ({{ic|iwlwifi}} in this example) to idenfify the relevant message or further issues:
{{hc|$ dmesg <nowiki>|</nowiki> grep iwlwifi|<nowiki>
[  12.342694] iwlwifi 0000:02:00.0: irq 44 for MSI/MSI-X
[  12.353466] iwlwifi 0000:02:00.0: loaded firmware version build 35138 op_mode iwldvm
[  12.430317] iwlwifi 0000:02:00.0: CONFIG_IWLWIFI_DEBUG disabled
[  12.430341] iwlwifi 0000:02:00.0: Detected Intel(R) Corporation WiFi Link 5100 AGN, REV=0x6B
If the kernel module is successfully loaded and the interface is up, you can skip the next section.
=== Installing driver/firmware ===
Check the following lists to discover if your card is supported:
* The [https://help.ubuntu.com/community/WifiDocs/WirelessCardsSupported Ubuntu Wiki] has a good list of wireless cards and whether or not they are supported either in the Linux kernel or by a user-space driver (includes driver name).
* [http://linux-wless.passys.nl/ Linux Wireless Support] and The Linux Questions' [http://www.linuxquestions.org/hcl/index.php?cat=10 Hardware Compatibility List] (HCL) also have a good database of kernel-friendly hardware.
* The [http://wireless.kernel.org/en/users/Devices kernel page] additionally has a matrix of supported hardware.
If your wireless card is listed above, follow the [[#Troubleshooting drivers and firmware]] subsection of this page, which contains information about installing drivers and firmware of some specific wireless cards. Then [[#Check the driver status|check the driver status]] again.
If your wireless card is not listed above, it is likely supported only under Windows (some Broadcom, 3com, etc). For these, you can try to use [[#ndiswrapper|ndiswrapper]].
== Wireless management ==
Assuming that your drivers are installed and working properly, you will need to choose a method of managing your wireless connections. The following subsections will help you decide.
Procedure and tools required will depend on several factors:
* The desired nature of configuration management; from a completely manual command line procedure to an automated solution with graphical front-ends.
* The encryption type (or lack thereof) which protects the wireless network.
* The need for network profiles, if the computer will frequently change networks (such as a laptop).
* Whatever is your choice, '''you should try to connect using the manual method first'''. This will help you understand the different steps that are required and troubleshoot possible problems.
* If possible (e.g. if you manage your Wi-Fi access point), try connecting with no encryption, to check that everything works. Then try using encryption, either WEP (simple to configure, but crackable in a matter of seconds), WPA or WPA2.
The following table shows the different methods that can be used to activate and manage a wireless connection, depending on the encryption and management types, and the various tools that are required. Although there may be other possibilities, these are the most frequently used:
{| class="wikitable" border="1"
! Management method || Interface activation || Wireless connection management <br>(/=alternatives) || Assigning IP address <br>(/=alternatives)
| [[#Manual setup|Manually managed]], <br>with no or WEP encryption || [[Core Utilities#ip|ip]] || {{Pkg|iw}} / [https://www.archlinux.org/packages/?name=wireless_tools iwconfig] || [[Core Utilities#ip|ip]] / {{Pkg|dhcpcd}} / {{Pkg|dhclient}}
| [[#Manual setup|Manually managed]], <br>with WPA or WPA2 PSK encryption || [[Core Utilities#ip|ip]] || {{Pkg|iw}} / [https://www.archlinux.org/packages/?name=wireless_tools iwconfig] + [[WPA supplicant|wpa_supplicant]] || [[Core Utilities#ip|ip]] / {{Pkg|dhcpcd}} / {{Pkg|dhclient}}
| [[#Automatic setup|Automatically managed]], <br>with network profiles support || colspan="3" align="center" | [[netctl]], [[Wicd]], [[NetworkManager]], etc.<br>
These tools pull in the required dependencies from the list of packages in the manual method.
=== Manual setup ===
Just like other network interfaces, the wireless ones are controlled with {{ic|ip}} from the {{Pkg|iproute2}} package. The package {{Pkg|wireless_tools}} then provides a basic set of tools for managing the wireless connection, however, these tools are deprecated in favor of the {{Pkg|iw}} tool. If ''iw'' does not work with your card, you can use ''wireless_tools'', the table below gives an overview of comparable commands with both (see [http://wireless.kernel.org/en/users/Documentation/iw/replace-iwconfig] for more examples). Additionally, the {{Pkg|wpa_supplicant}} package is required for WPA/WPA2 encryption. These powerful user-space tools work extremely well and allow complete manual control of wireless connection.
* Examples in this section assume that your wireless device is {{ic|wlan0}} and that you are connecting to {{ic|''your_essid''}} wifi access point. Replace both accordingly.
* Note that most of the commands have to be executed with [[Users and Groups|root permissions]]. Executed with normal user rights, some of the commands (e.g. ''iwlist''), will exit without error but not produce the correct output either, which can be confusing.
{| class="wikitable" border="1"
! ''iw'' command
! ''wireless_tools'' command
! Description
| iw dev wlan0 link
| iwconfig wlan0
| Getting link status.
| iw dev wlan0 scan
| iwlist wlan0 scan
| Scanning for available access points.
| iw dev wlan0 set type ibss
| iwconfig wlan0 mode ad-hoc
| Setting the operation mode to ''ad-hoc''.
| iw dev wlan0 connect ''your_essid''
| iwconfig wlan0 essid ''your_essid''
| Connecting to open network.
| iw dev wlan0 connect ''your_essid'' 2432
| iwconfig wlan0 essid ''your_essid'' freq 2432M
| Connecting to open network specifying channel.
| iw dev wlan0 connect ''your_essid'' key 0:''your_key''
| iwconfig wlan0 essid ''your_essid'' key ''your_key''
| Connecting to WEP encrypted network using hexadecimal key.
| iw dev wlan0 connect ''your_essid'' key 0:''your_key''
| iwconfig wlan0 essid ''your_essid'' key s:''your_key''
| Connecting to WEP encrypted network using ASCII key.
| iw dev wlan0 set power_save on
| iwconfig wlan0 power on
| Enabling power save.
{{Note|Depending on your hardware and encryption type, some of these steps may not be necessary. Some cards are known to require interface activation and/or access point scanning before being associated to an access point and being given an IP address. Some experimentation may be required. For instance, WPA/WPA2 users may try to directly activate their wireless network from step [[#Association]].}}
==== Getting some useful information ====
{{Tip|See [http://wireless.kernel.org/en/users/Documentation/iw official documentation] of the ''iw'' tool for more examples.}}
* First you need to find the name of wireless interface. You can do it with following command:
{{hc|$ iw dev|
Interface '''wlan0'''
ifindex 3
wdev 0x1
addr 12:34:56:78:9a:bc
type managed
channel 1 (2412 MHz), width: 40 MHz, center1: 2422 MHz
* To check link status, use following command. Example output when not connected to an AP:
{{hc|$ iw dev wlan0 link|
Not connected.
When connected to an AP, you will see something like:
{{hc|$ iw dev wlan0 link|
Connected to 12:34:56:78:9a:bc (on wlan0)
freq: 2412
RX: 33016518 bytes (152703 packets)
TX: 2024638 bytes (11477 packets)
signal: -53 dBm
tx bitrate: 150.0 MBit/s MCS 7 40MHz short GI
bss flags: short-preamble short-slot-time
dtim period: 1
beacon int: 100
* You can get statistic information, such as the amount of tx/rx bytes, signal strength etc., with following command:
{{hc|$ iw dev wlan0 station dump|
Station 12:34:56:78:9a:bc (on wlan0)
inactive time: 1450 ms
rx bytes: 24668671
rx packets: 114373
tx bytes: 1606991
tx packets: 8557
tx retries: 623
tx failed: 1425
signal:  -52 dBm
signal avg: -53 dBm
tx bitrate: 150.0 MBit/s MCS 7 40MHz short GI
authorized: yes
authenticated: yes
preamble: long
WMM/WME: yes
MFP: no
TDLS peer: no
==== Interface activation ====
''(Optional, but may be required)''
Some cards require that the kernel interface be activated before you can use the ''iw'' tool or ''wireless_tools'':
# ip link set wlan0 up
{{Note|If you get errors like {{ic|RTNETLINK answers: Operation not possible due to RF-kill}}, make sure that hardware switch is ''on''. See [[#Rfkill caveat]] for details.}}
To verify that the interface is up, inspect the output of the following command:
{{hc|# ip link show wlan0|
3: wlan0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc mq state DOWN mode DORMANT group default qlen 1000
    link/ether 12:34:56:78:9a:bc brd ff:ff:ff:ff:ff:ff
The {{ic|UP}} in {{ic|<BROADCAST,MULTICAST,UP,LOWER_UP>}} is what indicates the interface is up, not the later {{ic|state DOWN}}.
==== Access point discovery ====
See what access points are available:
# iw dev wlan0 scan | less
{{Note|If it displays {{ic|Interface doesn't support scanning}}, then you probably forgot to install the firmware. In some cases this message is also displayed when not running ''iw'' as root.}}
{{Tip|Depending on your location, you might need to set the correct [[#Regulatory domain|regulatory domain]] in order to see all available networks.}}
The important points to check:
* '''SSID:''' the name of the network.
* '''Signal:''' is reported in a wireless power ratio in dbm (e.g. from -100 to 0). The closer the negative value gets to zero, the better the signal. Observing the reported power on a good quality link and a bad one should give an idea about the individual range.
* '''Security:''' it is not reported directly, check the line starting with {{ic|capability}}. If there is {{ic|Privacy}}, for example {{ic|capability: ESS Privacy ShortSlotTime (0x0411)}}, then the network is protected somehow.
** If you see an {{ic|RSN}} information block, then the network is protected by [[Wikipedia:Robust Security Network|Robust Security Network]] protocol, also known as WPA2.
** If you see an {{ic|WPA}} information block, then the network is protected by [[Wikipedia:Wi-Fi Protected Access|Wi-Fi Protected Access]] protocol.
** In the {{ic|RSN}} and {{ic|WPA}} blocks you may find the following information:
*** '''Group cipher:''' value in TKIP, CCMP, both, others.
*** '''Pairwise ciphers:''' value in TKIP, CCMP, both, others. Not necessarily the same value than Group cipher.
*** '''Authentication suites:''' value in PSK, 802.1x, others. For home router, you'll usually find PSK (''i.e.'' passphrase). In universities, you are more likely to find 802.1x suite which requires login and password. Then you will need to know which key management is in use (e.g. EAP), and what encapsulation it uses (e.g. PEAP). Find more details at [[Wikipedia:Authentication protocol]] and the sub-articles.
** If you do not see neither {{ic|RSN}} nor {{ic|WPA}} blocks but there is {{ic|Privacy}}, then WEP is used.
==== Operating mode ====
''(Optional, but may be required)''
At this step you might need to set the proper operating mode of the wireless card. More specifically, if you are going to connect an [[Ad-hoc networking|ad-hoc network]], you need to set the operating mode to {{ic|ibss}}:
# iw dev wlan0 set type ibss
{{Note|Changing the operating mode on some cards might require the wireless interface to be ''down'' ({{ic|ip link set wlan0 down}}).}}
==== Association ====
Depending on the encryption, you need to associate your wireless device with the access point to use and pass the encryption key.
* '''No encryption'''
# iw dev wlan0 connect ''your_essid''
* '''WEP'''
using a hexadecimal or ASCII key (the format is distinguished automatically, because a WEP key has a fixed length):
# iw dev wlan0 connect ''your_essid'' key 0:''your_key''
using a hexadecimal or ASCII key, specifying the third set up key as default (keys are counted from zero, four are possible):
# iw dev wlan0 connect ''your_essid'' key d:2:''your_key''
* '''WPA/WPA2'''
You need to edit the {{ic|/etc/wpa_supplicant.conf}} file as described in [[WPA_Supplicant]] and according to what you got from [[#Access point discovery]]. Then, issue this command:
# wpa_supplicant -i wlan0 -c /etc/wpa_supplicant.conf
This is assuming your device uses the {{ic|wext}} driver. If this does not work, you may need to adjust these options.
If connected successfully, continue in a new terminal (or quit {{ic|wpa_supplicant}} with {{ic|Ctrl+c}} and add the {{ic|-B}} switch to the above command to run it in the background). [[WPA_Supplicant]] contains more information and troubleshooting.
Regardless of the method used, you can check if you have associated successfully:
# iw dev wlan0 link
==== Getting an IP address ====
{{Note|See [[Network Configuration#Configure the IP address]] for more examples. This part is identical.}}
Finally, provide an IP address to the network interface. Simple examples are:
# dhcpcd wlan0
# dhclient wlan0
for DHCP, or
# ip addr add dev wlan0
# ip route add default via
for static IP addressing.
{{Tip|{{Pkg|dhcpcd}} contains a hook (enabled by default) to automatically launch [[WPA supplicant]] on wireless interfaces. It is started only if a configuration file at {{ic|/etc/wpa_supplicant.conf}} exists and no ''wpa_supplicant'' process is listening on that interface. In most cases, you do not need to create any [[#Manual wireless connection at boot using systemd and dhcpcd|custom service]], just enable {{ic|dhcpcd@''interface''}}.}}
==== Custom startup scripts/services ====
Although the manual configuration method will help troubleshoot wireless problems, you will have to re-type every command each time you reboot. You can also quickly write a shell script to automate the whole process, which is still a quite convenient way of managing network connection while keeping full control over your configuration. You can find some examples in this section.
===== Manual wireless connection at boot using systemd and dhcpcd =====
This example uses [[systemd]] for start up, [[WPA supplicant]] for connecting, and {{Pkg|dhcpcd}} for assigning an IP address.
{{Note|Make sure that {{Pkg|wpa_supplicant}} is installed and create {{ic|/etc/wpa_supplicant.conf}}. See [[WPA supplicant]] for details.}}
Create a systemd unit, e.g {{ic|/etc/systemd/system/network-wireless@.service}}:
Description=Wireless network connectivity (%i)
ExecStart=/usr/bin/ip link set dev %i up
ExecStart=/usr/bin/wpa_supplicant -B -i %i -c /etc/wpa_supplicant.conf
ExecStart=/usr/bin/dhcpcd %i
ExecStop=/usr/bin/ip link set dev %i down
Enable the unit and start it, passing the name of the interface:
# systemctl enable network-wireless@wlan0.service
# systemctl start network-wireless@wlan0.service
===== Systemd with wpa_supplicant and static IP =====
{{Note|Make sure that {{Pkg|wpa_supplicant}} is installed and create {{ic|/etc/wpa_supplicant.conf}}. See [[WPA supplicant]] for details.}}
First create configuration file for the [[systemd]] service, replace {{ic|''interface''}} with proper interface name:
Create a systemd unit file:
Description=Wireless network connectivity (%i)
ExecStart=/usr/bin/ip link set dev %i up
ExecStart=/usr/bin/wpa_supplicant -B -i %i -c /etc/wpa_supplicant.conf
ExecStart=/usr/bin/ip addr add ${address}/${netmask} broadcast ${broadcast} dev %i
ExecStart=/usr/bin/ip route add default via ${gateway}
ExecStop=/usr/bin/ip addr flush dev %i
ExecStop=/usr/bin/ip link set dev %i down
Enable the unit and start it, passing the name of the interface:
# systemctl enable network-wireless@wlan0.service
# systemctl start network-wireless@wlan0.service
=== Automatic setup ===
There are many solutions to choose from, but remember that all of them are mutually exclusive; you should not run two daemons simultaneously. The following table compares the different connection managers, additional notes are in subsections below.
{| class="wikitable" border="1"
! Connection manager || Network <br>profiles <br>support || Roaming <br>(auto connect dropped <br>or changed location) || [[Wikipedia:point-to-point protocol|PPP]] support <br>(e.g. 3G modem) || Official <br>GUI || Console tools
| [[Connman]] || Yes || Yes || Yes || No || {{ic|connmanctl}}
| [[Netctl]] || Yes || Yes || Yes || No || {{ic|netctl}},{{ic|wifi-menu}}
| [[NetworkManager]] || Yes || Yes || Yes || Yes || {{ic|nmcli}}
| [[Wicd]] || Yes || Yes || No || Yes || {{ic|wicd-curses}}
==== Netctl ====
''netctl'' is a replacement for ''netcfg'' designed to work with systemd. It uses a profile based setup and is capable of detection and connection to a wide range of network types. This is no harder than using graphical tools.
See: [[Netctl]]
==== Wicd ====
Wicd is a network manager that can handle both wireless and wired connections. It is written in Python and Gtk with fewer dependencies than NetworkManager, making it an ideal solution for lightweight desktop users. Wicd is available in the [[Official Repositories|official repositories]].
See: [[Wicd]]
{{Note|[[wicd]] may cause excessive dropped connections with some drivers, while [[NetworkManager]] might work better.}}
==== NetworkManager ====
NetworkManager is an advanced network management tool that is enabled by default in most popular GNU/Linux distributions. In addition to managing wired connections, NetworkManager provides worry-free wireless roaming with an easy-to-use GUI program for selecting your desired network.
See: [[NetworkManager]]
{{Note|GNOME's {{Pkg|network-manager-applet}} also works under [[Xfce]] if you install {{AUR|xfce4-xfapplet-plugin}} (available in the [[Arch User Repository|AUR]]) first. Additionally, there are applets available for [[KDE]].}}
==== WiFi Radar ====
WiFi Radar is a Python/PyGTK2 utility for managing wireless (and '''only''' wireless) profiles. It enables you to scan for available networks and create profiles for your preferred networks.
See: [[Wifi Radar]]
== Troubleshooting ==
This section contains general troubleshooting tips, not strictly related to problems with drivers or firmware. For such topics, see next section.
{{Out of date|Commands in following subsections need updating according to [[ArchWiki:Requests#wireless_tools_-.3E_iw|wireless_tools -> iw]] transition.}}
=== Rfkill caveat ===
Many laptops have a hardware button (or switch) to turn off wireless card, however, the card can also be blocked by kernel. This can be handled by {{Pkg|rfkill}}. Use ''rfkill'' to show the current status:
{{hc|# rfkill list|
0: phy0: Wireless LAN
Soft blocked: yes
Hard blocked: yes
If the card is ''hard-blocked'', use the hardware button (switch) to unblock it. If the card is not ''hard-blocked'' but ''soft-blocked'', use the following command:
# rfkill unblock wifi
{{Note|It is possible that the card will go from ''hard-blocked'' and ''soft-unblocked'' state into ''hard-unblocked'' and ''soft-blocked'' state by pressing the hardware button (i.e. the ''soft-blocked'' bit is just switched no matter what). This can be adjusted by tuning some options of the {{ic|rfkill}} [[Kernel modules|kernel module]].}}
More info: http://askubuntu.com/questions/62166/siocsifflags-operation-not-possible-due-to-rf-kill
=== Regulatory domain ===
For example, the {{ic|iwl3945}} driver is by default configured to only work with networks on channels 1-11. Higher frequency bands are not allowed in some parts of the world (e.g. the US). In the EU however, channels 12 and 13 are used quite commonly (and Japan allows for channel 14). If the regulatory domain is set to e.g. US, then networks using higher channels will not show up in the scan.
It is possible to configure the [http://wireless.kernel.org/en/developers/Documentation/cfg80211 cfg80211] kernel module to use specific regulatory domain by adding e.g. {{ic|1=options cfg80211 ieee80211_regdom=EU}} to {{ic|/etc/modprobe.d/modprobe.conf}} (see [[Kernel modules]] for details).
{{Tip|Check the {{ic|Frequencies:}} block in the output of {{ic|iw list}} to see which frequencies are allowed for your card.}}
An alternative configuration would be installing the {{Pkg|crda}} package and editing {{ic|/etc/conf.d/wireless-regdom}} (the file is actually provided by {{Pkg|wireless-regdb}} which is a dependency of {{Pkg|crda}}).
=== Observing Logs ===
A good first measure to troubleshoot is to analyze the system's logfiles first. In order not to manually parse through them all, it can help to open a second terminal/console window and watch the kernels messages with
$ dmesg -w
while performing the action, e.g. the wireless association attempt.
When using a tool for network management, the same can be done for systemd with
# journalctl -f
The individual tools used in this article further provide options for more detailed debugging output, which can be used in a second step of the analysis, if required.
=== Power saving ===
See [[Power saving#Network interfaces]].
=== Failed to get IP address ===
* If getting an IP address repeatedly fails using the default {{Pkg|dhcpcd}} client, try installing and using {{Pkg|dhclient}} instead. Do not forget to select ''dhclient'' as the primary DHCP client in your [[#Automatic setup|connection manager]]!
* If you can get an IP address for a wired interface and not for a wireless interface, try disabling the wireless card's power saving features:
# iwconfig wlan0 power off
* If you get a timeout error due to a ''waiting for carrier'' problem, then you might have to set the channel mode to {{ic|auto}} for the specific device:
# iwconfig wlan0 channel auto
Before changing the channel to auto, make sure your wireless interface is down. After it has successfully changed it, you can bring the interface up again and continue from there.
=== Connection always times out ===
The driver may suffer from a lot of tx excessive retries and invalid misc errors for some unknown reason, resulting in a lot of packet loss and keep disconnecting, sometimes instantly. Following tips might be helpful.
==== Lowering the rate ====
Try setting lower rate, for example 5.5M:
# iwconfig wlan0 rate 5.5M auto
Fixed option should ensure that the driver does not change the rate on its own, thus making the connection a bit more stable:
# iwconfig wlan0 rate 5.5M fixed
==== Lowering the txpower ====
You can try lowering the transmit power as well. This may save power as well:
# iwconfig wlan0 txpower 5
Valid settings are from {{ic|0}} to {{ic|20}}, {{ic|auto}} and {{ic|off}}.
==== Setting rts and fragmentation thresholds ====
Default iwconfig options have rts and fragmentation thresholds off. These options are particularly useful when there are many adjacent APs or in a noisy environment.
The minimum value for fragmentation value is 256 and maximum is 2346. In many windows drivers the maximum is the default value:
# iwconfig wlan0 frag 2346
For rts minimum is 0, maximum is 2347. Once again windows drivers often use maximum as the default:
# iwconfig wlan0 rts 2347
=== Random disconnections ===
==== Cause #1 ====
If dmesg says {{ic|1=wlan0: deauthenticating from MAC by local choice (reason=3)}} and you lose your Wi-Fi connection, it is likely that you have a bit too aggressive power-saving on your Wi-Fi card[http://us.generation-nt.com/answer/gentoo-user-wireless-deauthenticating-by-local-choice-help-204640041.html]. Try disabling the wireless card's power-saving features:
# iwconfig wlan0 power off
See [[Power saving]] for tips on how to make it permanent (just specify {{ic|off}} instead of {{ic|on}}).
If your card does not support {{ic|iwconfig wlan0 power off}}, check the '''BIOS''' for power management options. Disabling PCI-Express power management in the BIOS of a Lenovo W520 resolved this issue.
==== Cause #2 ====
If you are experiencing frequent disconnections and dmesg shows messages such as
{{ic|1=ieee80211 phy0: wlan0: No probe response from AP xx:xx:xx:xx:xx:xx after 500ms, disconnecting}}
try changing the channel bandwidth to {{ic|20MHz}} through your router's settings page.
== Troubleshooting drivers and firmware ==
This section covers methods and procedures for installing kernel modules and ''firmware'' for specific chipsets, that differ from generic method.
See [[Kernel modules]] for general informations on operations with modules.
=== Ralink ===
==== rt2x00 ====
Unified driver for Ralink chipsets (it replaces {{ic|rt2500}}, {{ic|rt61}}, {{ic|rt73}}, etc). This driver has been in the Linux kernel since 2.6.24, you only need to load the right module for the chip: {{ic|rt2400pci}}, {{ic|rt2500pci}}, {{ic|rt2500usb}}, {{ic|rt61pci}} or {{ic|rt73usb}} which will autoload the respective {{ic|rt2x00}} modules too.
A list of devices supported by the modules is available at the project's [http://rt2x00.serialmonkey.com/wiki/index.php/Hardware homepage].
; Additional notes
* Since kernel 3.0, rt2x00 includes also these drivers: {{ic|rt2800pci}}, {{ic|rt2800usb}}.
* Since kernel 3.0, the staging drivers {{ic|rt2860sta}} and {{ic|rt2870sta}} are replaced by the mainline drivers {{ic|rt2800pci}} and {{ic|rt2800usb}}<sup>[https://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commitdiff;h=fefecc6989b4b24276797270c0e229c07be02ad3]</sup>.
* Some devices have a wide range of options that can be configured with {{ic|iwpriv}}. These are documented in the [http://web.ralinktech.com/ralink/Home/Support/Linux.html source tarballs] available from Ralink.
==== rt3090 ====
For devices which are using the rt3090 chipset it should be possible to use {{ic|rt2800pci}} driver, however, is not working with this chipset very well (e.g. sometimes it's not possible to use higher rate than 2Mb/s).
The best way is to use the {{AUR|rt3090}} driver from [[AUR]]. Make sure to [[Kernel modules#Blacklisting|blacklist]] the {{ic|rt2800pci}} module and setup the {{ic|rt3090sta}} module to [[Kernel modules#Loading|load]] at boot.
{{Note|This driver also works with rt3062 chipsets.}}
==== rt3290 ====
The rt3290 chipset is recognised by the kernel {{ic|rt2800pci}} module. However, some users experience problems and reverting to a patched Ralink driver seems to be beneficial in these [https://bbs.archlinux.org/viewtopic.php?id=161952 cases].
==== rt3573 ====
New chipset as of 2012. It may require proprietary drivers from Ralink. Different manufacturers use it, see the [https://bbs.archlinux.org/viewtopic.php?pid=1164228#p1164228 Belkin N750 DB wireless usb adapter] forums thread.
==== rt5572 ====
New chipset as of 2012 with support for 5 Ghz bands. It may require proprietary drivers from Ralink and some effort to compile them. At the time of writing a how-to on compilation is available for a DLINK DWA-160 rev. B2 [http://bernaerts.dyndns.org/linux/229-ubuntu-precise-dlink-dwa160-revb2 here].
=== Realtek ===
==== rtl8192cu ====
The driver is now in the kernel, but many users have reported being unable to make a connection although scanning for networks does work.
The {{AUR|dkms-8192cu}} package in the AUR may be a better choice for some users.
==== rtl8192e ====
The driver is part of the current kernel package. The module initialization may fail at boot giving this error message:
rtl819xE:ERR in CPUcheck_firmware_ready()
rtl819xE:ERR in init_firmware() step 2
rtl819xE:ERR!!! _rtl8192_up(): initialization is failed!
r8169 0000:03:00.0: eth0: link down
A workaround is to simply unload the module:
# modprobe -r r8192e_pci
and reload the module (after a pause):
# modprobe r8192e_pci
==== rtl8188eu ====
Some dongles, like the TP-Link TL-WN725N v2 (not sure, but it seems that uses the rtl8179 chipset), use chipsets compatible with this driver. In order to use it you have to install the {{AUR|dkms-8188eu}} package in the AUR.
=== Atheros ===
The [http://madwifi-project.org/ MadWifi team] currently maintains three different drivers for devices with Atheros chipset:
* {{ic|madwifi}} is an old, obsolete driver. Not present in Arch kernel since<sup>[https://mailman.archlinux.org/pipermail/arch-dev-public/2011-June/020669.html]</sup>.
* {{ic|ath5k}} is newer driver, which replaces the {{ic|madwifi}} driver. Currently a better choice for some chipsets, but not all chipsets are supported (see below)
* {{ic|ath9k}} is the newest of these three drivers, it is intended for newer Atheros chipsets. All of the chips with 802.11n capabilities are supported.
There are some other drivers for some Atheros devices. See [http://wireless.kernel.org/en/users/Drivers/Atheros#PCI_.2F_PCI-E_.2F_AHB_Drivers Linux Wireless documentation] for details.
==== ath5k ====
External resources:
* http://wireless.kernel.org/en/users/Drivers/ath5k
* http://wiki.debian.org/ath5k
If you find web pages randomly loading very slow, or if the device is unable to lease an IP address, try to switch from hardware to software encryption by loading the {{ic|ath5k}} module with {{ic|1=nohwcrypt=1}} option. See [[Kernel Modules#Options]] for details.
Some laptops may have problems with their wireless LED indicator flickering red and blue. To solve this problem, do:
# echo none > /sys/class/leds/ath5k-phy0::tx/trigger
# echo none > /sys/class/leds/ath5k-phy0::rx/trigger
For alternatives, see [https://bugzilla.redhat.com/show_bug.cgi?id=618232 this bug report].
==== ath9k ====
External resources:
* http://wireless.kernel.org/en/users/Drivers/ath9k
* http://wiki.debian.org/ath9k
In the unlikely event that you have stability issues that trouble you, you could try using the [http://wireless.kernel.org/en/users/Download compat-wireless] package.
An [https://lists.ath9k.org/mailman/listinfo/ath9k-devel ath9k mailing list] exists for support and development related discussions.
===== ASUS =====
With some ASUS laptops (tested with ASUS U32U series), it could help to add {{ic|1=options asus_nb_wmi wapf=1}} to {{ic|/etc/modprobe.d/asus_nb_wmi.conf}} to fix rfkill-related issues.
=== Intel ===
==== ipw2100 and ipw2200 ====
These modules are fully supported in the kernel, but they require additional firmware. Depending on which of the chipsets you have, [[pacman|install]] either {{Pkg|ipw2100-fw}} or {{Pkg|ipw2200-fw}}. Then [[Kernel modules#Manual module handling|reload]] the appropriate module.
{{Tip|You may use the following [[Kernel modules#Setting module options|module options]]:
* use the {{ic|1=rtap_iface=1}} option to enable the radiotap interface
* use the {{ic|1=led=1}} option to enable a front LED indicating when the wireless is connected or not
==== iwlegacy ====
[http://wireless.kernel.org/en/users/Drivers/iwlegacy iwlegacy] is the wireless driver for Intel's 3945 and 4965 wireless chips. The firmware is included in the {{Pkg|linux-firmware}} package.
[[udev]] should load the driver automatically, otherwise load {{ic|iwl3945}} or {{ic|iwl4965}} manually. See [[Kernel modules#Loading]] for details.
==== iwlwifi ====
==== iwlwifi ====
Line 700: Line 8:
options iwlwifi swcrypto=1</nowiki>}}
options iwlwifi swcrypto=1</nowiki>}}
==== Disabling LED blink ====
In case this does not work for you, you may try disabling power saving for your wireless adapter. For a permanent solution, add a new udev rule:
{{hc|/etc/udev/rules.d/80-iwlwifi.rules|<nowiki>ACTION=="add", SUBSYSTEM=="net", ATTR{address}=="<your_mac_address>", RUN+="/usr/bin/iw dev %k set power_save off"</nowiki>}}
{{Note|This works with the {{ic|iwlegacy}} and {{ic|iwlwifi}} drivers.}}
The default settings on the module are to have the LED blink on activity. Some people find this extremely annoying. To have the LED on solid when Wi-Fi is active, you can use the [[systemd#Temporary files|systemd-tmpfiles]]:
w /sys/class/leds/phy0-led/trigger - - - - phy0radio
Run {{ic|systemd-tmpfiles --create phy0-led.conf}} for the change to take effect, or reboot.
To see all the possible trigger values for this LED:
# cat /sys/class/leds/phy0-led/trigger
{{Tip|If you do not have {{ic|/sys/class/leds/phy0-led}}, you may try to use the {{ic|1=led_mode="1"}} [[Kernel modules#Setting module options|module option]]. It should be valid for both {{ic|iwlwifi}} and {{ic|iwlegacy}} drivers.}}
=== Broadcom ===
See [[Broadcom wireless]].
=== Other drivers/devices ===
==== Tenda w322u ====
Treat this Tenda card as an {{ic|rt2870sta}} device. See [[#rt2x00]].
==== orinoco ====
This should be a part of the kernel package and be installed already.
Some Orinoco chipsets are Hermes II. You can use the {{ic|wlags49_h2_cs}} driver instead of {{ic|orinoco_cs}} and gain WPA support. To use the driver, [[Kernel modules#Blacklisting|blacklist]] {{ic|orinoco_cs}} first.
==== prism54 ====
The driver {{ic|p54}} is included in kernel, but you have to download the appropriate firmware for your card from [http://linuxwireless.org/en/users/Drivers/p54#firmware this site] and install it into the {{ic|/usr/lib/firmware}} directory.
{{Note|There's also older, deprecated driver {{ic|prism54}}, which might conflict with the newer driver ({{ic|p54pci}} or {{ic|p54usb}}). Make sure to [[Kernel modules#Blacklisting|blacklist]] {{ic|prism54}}.}}
==== ACX100/111 ====
{{Warning|The drivers for these devices [https://mailman.archlinux.org/pipermail/arch-dev-public/2011-June/020669.html are broken] and do not work with newer kernel versions.}}
Packages: {{ic|tiacx}} {{ic|tiacx-firmware}} (deleted from official repositories and AUR)
See [http://sourceforge.net/apps/mediawiki/acx100/index.php?title=Main_Page official wiki] for details.
==== zd1211rw ====
[http://zd1211.wiki.sourceforge.net/ {{ic|zd1211rw}}] is a driver for the ZyDAS ZD1211 802.11b/g USB WLAN chipset, and it is included in recent versions of the Linux kernel. See [http://www.linuxwireless.org/en/users/Drivers/zd1211rw/devices] for a list of supported devices. You only need to [[pacman|install]] the firmware for the device, provided by the {{Pkg|zd1211-firmware}} package.
==== hostap_cs ====
[http://hostap.epitest.fi/ Host AP] is a Linux driver for wireless LAN cards based on Intersil's Prism2/2.5/3 chipset. The driver is included in Linux kernel.
{{Note|Make sure to [[Kernel_modules#Blacklisting|blacklist]] the {{ic|orinico_cs}} driver, it may cause problems.}}
=== ndiswrapper ===
Ndiswrapper is a wrapper script that allows you to use some Windows drivers in Linux. See the compatibility list [http://ndiswrapper.sourceforge.net/mediawiki/index.php/List here]. You will need the {{ic|.inf}} and {{ic|.sys}} files from your Windows driver. Be sure to use drivers appropriate to your architecture (x86 vs. x86_64).
{{Tip|If you need to extract these files from an {{ic|*.exe}} file, you can use {{Pkg|cabextract}}.}}
Follow these steps to configure ndiswrapper.
1. Install the driver to {{ic|/etc/ndiswrapper/*}}
# ndiswrapper -i filename.inf
2. List all installed drivers for ndiswrapper
$ ndiswrapper -l
3. Write the following configuration file:
ndiswrapper -m
depmod -a
Now the ndiswrapper install is almost finished; follow the instructions on [[Kernel modules#Loading]] to automatically load the module at boot.
The important part is making sure that ndiswrapper exists on this line, so just add it alongside the other modules. It would be best to test that ndiswrapper will load now, so:
# modprobe ndiswrapper
# iwconfig
and ''wlan0'' should now exist. Check this page if you are having problems:
[http://ndiswrapper.sourceforge.net/joomla/index.php?/component/option,com_openwiki/Itemid,33/id,installation/ Ndiswrapper installation wiki].
=== compat-drivers-patched ===
{{Out of date|{{AUR|compat-drivers-patched}} has reached end-of-life, {{AUR|backports-patched}} should be used instead}}
Patched compat wireless drivers correct the "fixed-channel -1" issue, whilst providing better injection. Please install the {{AUR|compat-drivers-patched}} package from the [[Arch User Repository|AUR]].
{{AUR|compat-drivers-patched}} does not conflict with any other package and the modules built reside in {{ic|/usr/lib/modules/''your_kernel_version''/updates}}.
These patched drivers come from the [http://wireless.kernel.org/ Linux Wireless project] and support many of the above mentioned chips such as:
ath5k ath9k_htc carl9170 b43 zd1211rw rt2x00 wl1251 wl12xx ath6kl brcm80211
Supported groups:
atheros ath iwlagn rtl818x rtlwifi wl12xx atlxx bt
It is also possible to build a specific module/driver or a group of drivers by editing the [[PKGBUILD]], particularly uncommenting the '''line #46'''. Here is an example of building the atheros group:
scripts/driver-select atheros
Please read the package's [[PKGBUILD]] for any other possible modifications prior to compilation and installation.
== See also ==
* [http://wireless.kernel.org/ The Linux Wireless project]
* [http://aircrack-ng.org/doku.php?id=install_drivers Aircrack-ng guide on installing drivers]

Revision as of 20:02, 1 December 2013


iwlwifi is the wireless driver for Intel's current wireless chips, such as 5100AGN, 5300AGN, and 5350AGN. See the full list of supported devices. The firmware is included in the linux-firmware package.

If you have problems connecting to networks in general or your link quality is very poor, try to disable 802.11n and enable software encryption:

options iwlwifi 11n_disable=1
options iwlwifi swcrypto=1

In case this does not work for you, you may try disabling power saving for your wireless adapter. For a permanent solution, add a new udev rule:

ACTION=="add", SUBSYSTEM=="net", ATTR{address}=="<your_mac_address>", RUN+="/usr/bin/iw dev %k set power_save off"