Difference between revisions of "Wireless network configuration"

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[[Category:Wireless Networking]]
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[[Category:Wireless networking]]
[[cs:Wireless Setup]]
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[[cs:Wireless network configuration]]
[[de:(W)LAN_und_Arch_Linux]]
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[[de:(W)LAN und Arch Linux]]
[[el:Wireless Setup]]
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[[el:Wireless network configuration]]
[[es:Wireless Setup]]
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[[es:Wireless network configuration]]
 
[[fr:Wifi]]
 
[[fr:Wifi]]
[[it:Wireless Setup]]
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[[it:Wireless network configuration]]
[[ja:Wireless Setup]]
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[[ja:ワイヤレス設定]]
[[nl:Wireless Setup]]
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[[nl:Wireless network configuration]]
 
[[ro:Wireless]]
 
[[ro:Wireless]]
[[ru:Wireless Setup]]
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[[ru:Wireless network configuration]]
[[th:Wireless Setup]]
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[[th:Wireless network configuration]]
[[tr:Kablosuz_bağlantı]]
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[[tr:Kablosuz bağlantı]]
[[zh-CN:Wireless Setup]]
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[[zh-cn:Wireless network configuration]]
 
{{Related articles start}}
 
{{Related articles start}}
{{Related|Network Configuration}}
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{{Related|Network configuration}}
{{Related|Software Access Point}}
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{{Related|Software access point}}
 
{{Related|Ad-hoc networking}}
 
{{Related|Ad-hoc networking}}
{{Related|Internet Sharing}}
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{{Related|Internet sharing}}
 +
{{Related|Wireless bonding}}
 
{{Related articles end}}
 
{{Related articles end}}
  
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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]].
 
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]].
  
{{Note|
+
{{Note|Udev is not perfect. If the proper module is not loaded by udev on boot, simply [[Kernel modules#Manual module handling|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 [[blacklist]] the unwanted module.}}
* 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.}}
 
{{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.}}
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=== Check the driver status ===
 
=== 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:
+
To check if the driver for your card has been loaded, check the output of the {{ic|lspci -k}} or {{ic|lsusb -v}} command, depending on if the card is connected by PCI(e) or USB. You should see that some kernel driver is in use, for example:
  
 
{{hc|$ lspci -k|<nowiki>
 
{{hc|$ lspci -k|<nowiki>
Line 46: Line 44:
 
</nowiki>}}
 
</nowiki>}}
  
{{Note|The internal Wi-Fi card in some laptops may actually be a USB device, so you should check these commands too:
+
{{Note|If the card is a USB device, running {{ic|<nowiki>dmesg | grep usbcore</nowiki>}} should give something like {{ic|usbcore: registered new interface driver rtl8187}} as output.}}
* {{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}}:
+
Also check the output of {{ic|ip link}} command to see if a wireless interface ([[Network configuration#Device names|usually]] it starts with the letter "w", e.g. {{ic|wlp2s1}}) 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
 
  # ip link set wlan0 up
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Check kernel messages for firmware being loaded:
 
Check kernel messages for firmware being loaded:
  
{{hc|$ dmesg <nowiki>|</nowiki> grep firmware|<nowiki>
+
{{hc|<nowiki>$ dmesg | grep firmware</nowiki>|<nowiki>
 
[  7.148259] iwlwifi 0000:02:00.0: loaded firmware version 39.30.4.1 build 35138 op_mode iwldvm
 
[  7.148259] iwlwifi 0000:02:00.0: loaded firmware version 39.30.4.1 build 35138 op_mode iwldvm
 
</nowiki>}}
 
</nowiki>}}
  
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:
+
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 identify the relevant message or further issues:
  
{{hc|$ dmesg <nowiki>|</nowiki> grep iwlwifi|<nowiki>
+
{{hc|<nowiki>$ dmesg | grep iwlwifi</nowiki>|<nowiki>
 
[  12.342694] iwlwifi 0000:02:00.0: irq 44 for MSI/MSI-X
 
[  12.342694] iwlwifi 0000:02:00.0: irq 44 for MSI/MSI-X
 
[  12.353466] iwlwifi 0000:02:00.0: loaded firmware version 39.31.5.1 build 35138 op_mode iwldvm
 
[  12.353466] iwlwifi 0000:02:00.0: loaded firmware version 39.31.5.1 build 35138 op_mode iwldvm
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Check the following lists to discover if your card is supported:
 
Check the following lists to discover if your card is supported:
  
 +
* See the table of [https://wireless.wiki.kernel.org/en/users/drivers existing Linux wireless drivers] and follow to the specific driver's page, which contains a list of supported devices. There is also a [https://wikidevi.com/wiki/List_of_Wi-Fi_Device_IDs_in_Linux List of Wi-Fi Device IDs in Linux].
 
* 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).
 
* 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.
 
* [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.
+
 
 +
Note that some vendors ship products that may contain different chip sets, even if the product identifier is the same. Only the usb-id (for USB devices) or pci-id (for PCI devices) is authoritative.
  
 
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 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]].
+
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]].
  
 
== Wireless management ==
 
== Wireless management ==
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* 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.
 
* 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.
 
* 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.
 +
* If you anticipate to connect the machine to different wireless networks over time, a tool which provides its own connection management may be easier to handle.
 
}}
 
}}
  
 
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:
 
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"
+
{| class="wikitable"
 
! Management method || Interface activation || Wireless connection management <br>(/=alternatives) || Assigning IP address <br>(/=alternatives)  
 
! 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 no or WEP encryption || [[Core utilities#ip|ip]] || {{Pkg|iw}} / [https://www.archlinux.org/packages/?name=wireless_tools iwconfig] || [[Core utilities#ip|ip]] / [[dhcpcd]] / {{Pkg|dhclient}} / [[networkd]]
 
|-
 
|-
| [[#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}}
+
| [[#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]] || [[Core utilities#ip|ip]] / [[dhcpcd]] / {{Pkg|dhclient}} / [[networkd]]
 
|-
 
|-
 
| [[#Automatic setup|Automatically managed]], <br>with network profiles support || colspan="3" align="center" | [[netctl]], [[Wicd]], [[NetworkManager]], etc.<br>
 
| [[#Automatic setup|Automatically managed]], <br>with network profiles support || colspan="3" align="center" | [[netctl]], [[Wicd]], [[NetworkManager]], etc.<br>
Line 116: Line 114:
 
=== Manual setup ===
 
=== 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.
+
Just like other network interfaces, the wireless ones are controlled with ''ip'' from the {{Pkg|iproute2}} package.
 +
 
 +
You will need to install a basic set of tools for managing the wireless connection. Either:
 +
:*{{Pkg|iw}} - only supports the nl80211 (netlink) standard. It does not support the older WEXT (Wireless EXTentions) standard. If ''iw'' does not see your card, this may be the reason.
 +
:or
 +
:*{{Pkg|wireless_tools}} - currently deprecated, but still widely supported. Use this for modules using the WEXT standard.
 +
 
 +
For WPA/WPA2 encryption, you will also need:
 +
:*{{Pkg|wpa_supplicant}} - works with both WEXT and nl80211.
 +
 
 +
The table below gives an overview of comparable commands for ''iw'' and ''wireless_tools'' (see [http://wireless.kernel.org/en/users/Documentation/iw/replace-iwconfig iw replaces iwconfig] for more examples). These user-space tools work extremely well and allow complete manual control of wireless connection.
  
 
{{Note|
 
{{Note|
* 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.  
+
* {{Pkg|iw}} and {{Pkg|wpa_supplicant}} are provided on the installation medium.
* 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.
+
* Examples in this section assume that your wireless device interface is {{ic|wlan0}} and that you are connecting to {{ic|''your_essid''}} wifi access point. Replace both accordingly. To find your wireless device interface, see [[#Getting some useful information]].
 +
* 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"
+
{| class="wikitable"
 
! ''iw'' command
 
! ''iw'' command
 
! ''wireless_tools'' command
 
! ''wireless_tools'' command
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| Connecting to open network specifying channel.
 
| Connecting to open network specifying channel.
 
|-
 
|-
| iw dev wlan0 connect ''your_essid'' key 0:''your_key''
+
| rowspan="2" | iw dev wlan0 connect ''your_essid'' key 0:''your_key''
 
| iwconfig wlan0 essid ''your_essid'' key ''your_key''
 
| iwconfig wlan0 essid ''your_essid'' key ''your_key''
 
| Connecting to WEP encrypted network using hexadecimal 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''
 
| iwconfig wlan0 essid ''your_essid'' key s:''your_key''
 
| Connecting to WEP encrypted network using ASCII key.
 
| Connecting to WEP encrypted network using ASCII key.
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==== Interface activation ====
 
==== Interface activation ====
  
''(Optional, but may be required)''
+
{{Tip|Usually this step is not required.}}
  
Some cards require that the kernel interface be activated before you can use the ''iw'' tool or ''wireless_tools'':
+
Some cards require that the kernel interface be activated before you can use ''iw'' or ''wireless_tools'':
  
 
  # ip link set wlan0 up
 
  # ip link set wlan0 up
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  # iw dev wlan0 scan | less
 
  # 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.}}
+
{{Note|If it displays {{ic|Interface does not 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.}}
+
{{Tip|Depending on your location, you might need to set the correct [[#Respecting the regulatory domain|regulatory domain]] in order to see all available networks.}}
  
 
The important points to check:
 
The important points to check:
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* '''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.  
 
* '''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.
 
* '''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|RSN}} information block, then the network is protected by [[Wikipedia:IEEE 802.11i-2004|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.
 
** 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:
 
** In the {{ic|RSN}} and {{ic|WPA}} blocks you may find the following information:
 
*** '''Group cipher:''' value in TKIP, CCMP, both, others.
 
*** '''Group cipher:''' value in TKIP, CCMP, both, others.
 
*** '''Pairwise ciphers:''' value in TKIP, CCMP, both, others. Not necessarily the same value than Group cipher.
 
*** '''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.
+
*** '''Authentication suites:''' value in PSK, 802.1x, others. For home router, you will 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.
+
** If you see neither {{ic|RSN}} nor {{ic|WPA}} blocks but there is {{ic|Privacy}}, then WEP is used.
  
 
==== Operating mode ====
 
==== Operating mode ====
  
''(Optional, but may be required)''
+
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}}:
 
+
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
 
  # iw dev wlan0 set type ibss
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==== Association ====
 
==== Association ====
  
Depending on the encryption, you need to associate your wireless device with the access point to use and pass the encryption key.
+
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''
+
  
 +
* '''No encryption''' {{bc|# iw dev wlan0 connect "''your_essid''"}}
 
* '''WEP'''
 
* '''WEP'''
 +
** using a hexadecimal or ASCII key (the format is distinguished automatically, because a WEP key has a fixed length): {{bc|# 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): {{bc|# iw dev wlan0 connect "''your_essid''" key d:2:''your_key''}}
 +
* '''WPA/WPA2''' According to what you got from [[#Access point discovery]], issue this command: {{bc|# wpa_supplicant -D nl80211,wext -i wlan0 -c <(wpa_passphrase "''your_SSID''" "''your_key''")}}
  
using a hexadecimal or ASCII key (the format is distinguished automatically, because a WEP key has a fixed length):
+
If this does not work, you may need to adjust the 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 on options and on how to create a permanent configuration file for the wireless access point.
# 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:
 
Regardless of the method used, you can check if you have associated successfully:
  
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==== Getting an IP address ====
 
==== Getting an IP address ====
  
{{Note|See [[Network Configuration#Configure the IP address]] for more examples. This part is identical.}}
+
{{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:
 
Finally, provide an IP address to the network interface. Simple examples are:
  
 
  # dhcpcd wlan0
 
  # dhcpcd wlan0
 
or
 
 
# dhclient wlan0
 
  
 
for DHCP, or
 
for DHCP, or
Line 324: Line 312:
 
for static IP addressing.
 
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''}}.}}
+
{{Tip|[[dhcpcd]] provides a [[dhcpcd#10-wpa_supplicant|hook]], which can be enabled to automatically launch [[WPA supplicant]] on wireless interfaces.}}
  
==== Custom startup scripts/services ====
+
==== Example ====
  
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.
+
Here is a complete example of setting up a wireless network with WPA supplicant and DHCP.
  
===== Manual wireless connection at boot using systemd and dhcpcd =====
+
# ip link set dev wlp13s1 up
 +
# wpa_supplicant -B -i wlp13s1 -c /etc/wpa_supplicant/wpa_supplicant.conf
 +
# dhcpcd wlp13s1
  
This example uses [[systemd]] for start up, [[WPA supplicant]] for connecting, and {{Pkg|dhcpcd}} for assigning an IP address.
+
And then to close the connection, you can simply disable the interface:
  
{{Note|Make sure that {{Pkg|wpa_supplicant}} is installed and create {{ic|/etc/wpa_supplicant.conf}}. See [[WPA supplicant]] for details.}}
+
# ip link set dev wlp13s1 down
  
Create a systemd unit, e.g {{ic|/etc/systemd/system/network-wireless@.service}}:
+
For a static IP, you would replace the dhcpcd command with
  
{{hc|/etc/systemd/system/network-wireless@.service|<nowiki>
+
  # ip addr add 192.168.0.10/24 broadcast 192.168.0.255 dev wlp13s1
[Unit]
+
# ip route add default via 192.168.0.1
Description=Wireless network connectivity (%i)
+
Wants=network.target
+
Before=network.target
+
BindsTo=sys-subsystem-net-devices-%i.device
+
After=sys-subsystem-net-devices-%i.device
+
 
+
[Service]
+
Type=oneshot
+
RemainAfterExit=yes
+
 
+
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
+
 
+
[Install]
+
WantedBy=multi-user.target
+
</nowiki>}}
+
 
+
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:
+
 
+
{{hc|/etc/conf.d/network-wireless@''interface''|<nowiki>
+
address=192.168.0.10
+
netmask=24
+
broadcast=192.168.0.255
+
gateway=192.168.0.1
+
</nowiki>}}
+
 
+
Create a systemd unit file:
+
 
+
{{hc|/etc/systemd/system/network-wireless@.service|<nowiki>
+
[Unit]
+
Description=Wireless network connectivity (%i)
+
Wants=network.target
+
Before=network.target
+
BindsTo=sys-subsystem-net-devices-%i.device
+
After=sys-subsystem-net-devices-%i.device
+
 
+
[Service]
+
Type=oneshot
+
RemainAfterExit=yes
+
EnvironmentFile=/etc/conf.d/network-wireless@%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
+
 
+
[Install]
+
WantedBy=multi-user.target
+
</nowiki>}}
+
  
Enable the unit and start it, passing the name of the interface:
+
And before disabling the interface you would first flush the IP address and gateway:
  
  # systemctl enable network-wireless@wlan0.service
+
  # ip addr flush dev wlp13s1
  # systemctl start network-wireless@wlan0.service
+
  # ip route flush dev wlp13s1
  
 
=== Automatic setup ===
 
=== Automatic setup ===
Line 414: Line 340:
 
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.
 
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"
+
{| class="wikitable"
! 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
+
! 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}}
 
| [[Connman]] || Yes || Yes || Yes || No || {{ic|connmanctl}}
 
|-
 
|-
| [[Netctl]] || Yes || Yes || Yes || No || {{ic|netctl}},{{ic|wifi-menu}}
+
| [[netctl]] || Yes || Yes || Yes || No || {{ic|netctl}},{{ic|wifi-menu}}
 
|-
 
|-
| [[NetworkManager]] || Yes || Yes || Yes || Yes || {{ic|nmcli}}
+
| [[NetworkManager]] || Yes || Yes || Yes || Yes || {{ic|nmcli}},{{ic|nmtui}}
 
|-
 
|-
 
| [[Wicd]] || Yes || Yes || No || Yes || {{ic|wicd-curses}}
 
| [[Wicd]] || Yes || Yes || No || Yes || {{ic|wicd-curses}}
 +
|-
 +
| [[Wifi Radar]] || Yes || ? || ? || Yes || {{ic|wifi-radar}}
 
|}
 
|}
  
==== Netctl ====
+
==== Connman ====
  
''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.
+
''ConnMan'' is an alternative to ''NetworkManager'' and ''Wicd'', designed to be light on resources making it ideal for netbooks, and other mobile devices. It is modular in design takes advandage of the dbus API and provides proper abstraction on top of ''wpa_supplicant''.  
  
See: [[Netctl]]
+
See [[Connman]].
  
==== Wicd ====
+
==== netctl ====
  
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]].
+
''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: [[Wicd]]
+
See [[netctl]].
  
{{Note|[[wicd]] may cause excessive dropped connections with some drivers, while [[NetworkManager]] might work better.}}
+
==== Wicd ====
  
==== NetworkManager ====
+
''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''.
  
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 [[Wicd]].
  
See: [[NetworkManager]]
+
==== 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.
  
{{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]].}}
+
See [[NetworkManager]].
  
 
==== WiFi Radar ====
 
==== 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.
+
''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]]
+
See [[Wifi Radar]].
  
 
== Troubleshooting ==
 
== Troubleshooting ==
  
This section contains general troubleshooting tips, not strictly related to problems with drivers or firmware. For such topics, see next section.
+
This section contains general troubleshooting tips, not strictly related to problems with drivers or firmware. For such topics, see next section [[#Troubleshooting drivers and firmware]].
  
{{Out of date|Commands in following subsections need updating according to [[ArchWiki:Requests#wireless_tools_-.3E_iw|wireless_tools -> iw]] transition.}}
+
=== Temporary internet access ===
 +
 
 +
If you have problematic hardware and need internet access to, for example, download some software or get help in forums, you can make use of Android's built-in feature for internet sharing via USB cable. See [[Android tethering#USB tethering]] for more information.
  
 
=== Rfkill caveat ===
 
=== Rfkill caveat ===
Line 474: Line 406:
 
  # rfkill unblock wifi
 
  # 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]].}}
+
{{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 module]].}}
  
More info: http://askubuntu.com/questions/62166/siocsifflags-operation-not-possible-due-to-rf-kill
+
Hardware buttons to toggle wireless cards are handled by a vendor specific [[kernel module]], frequently these are [https://lwn.net/Articles/391230/ WMI] modules. Particularly for very new hardware models, it happens that the model is not fully supported in the latest stable kernel yet. In this case it often helps to search the kernel bug tracker for information and report the model to the maintainer of the respective vendor kernel module, if it has not happened already.
  
=== Regulatory domain ===
+
See also: http://askubuntu.com/questions/62166/siocsifflags-operation-not-possible-due-to-rf-kill
  
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.
+
=== Respecting the regulatory domain ===
  
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).
+
The [[wikipedia:IEEE_802.11#Regulatory_domains_and_legal_compliance|regulatory domain]], or "regdomain", is used to reconfigure wireless drivers to make sure that wireless hardware usage complies with local laws set by the FCC, ETSI and other organizations. Regdomains use [[wikipedia:ISO_3166-1_alpha-2|ISO 3166-1 alpha-2 country codes]]. For example, the regdomain of the United States would be "US", China would be "CN", etc.
  
{{Tip|Check the {{ic|Frequencies:}} block in the output of {{ic|iw list}} to see which frequencies are allowed for your card.}}
+
Regdomains affect the availability of wireless channels. In the 2.4GHz band, the allowed channels are 1-11 for the US, 1-14 for Japan, and 1-13 for most of the rest of the world. In the 5GHz band, the rules for allowed channels are much more complex. In either case, consult [[wikipedia:List_of_WLAN_channels|this list of WLAN channels]] for more detailed information.
  
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}}).
+
Regdomains also affect the limit on the [[wikipedia:Equivalent_isotropically_radiated_power|effective isotropic radiated power (EIRP)]] from wireless devices. This is derived from transmit power/"tx power", and is measured in [[wikipedia:DBm|dBm/mBm (1dBm=100mBm) or mW (log scale)]]. In the 2.4GHz band, the maximum is 30dBm in the US and Canada, 20dBm in most of Europe, and 20dB-30dBm for the rest of the world. In the 5GHz band, maximums are usually lower. Consult the [http://git.kernel.org/cgit/linux/kernel/git/linville/wireless-regdb.git/tree/db.txt wireless-regdb] for more detailed information (EIRP dBm values are in the second set of brackets for each line).
  
=== Observing Logs ===  
+
Misconfiguring the regdomain can be useful - for example, by allowing use of an unused channel when other channels are crowded, or by allowing an increase in tx power to widen transmitter range. However, '''this is not recommended''' as it could break local laws and cause interference with other radio devices.
 +
 
 +
To configure the regdomain, install {{Pkg|crda}} and reboot (to reload the {{ic|cfg80211}} module and all related drivers). Check the boot log to make sure that CRDA is being called by {{ic|cfg80211}}:
 +
 
 +
$ dmesg | grep cfg80211
 +
 
 +
The current regdomain can be set to the United States with:
 +
 
 +
# iw reg set US
 +
 
 +
And queried with:
 +
 
 +
$ iw reg get
 +
 
 +
{{Note|Your device may be set to country "00", which is the "world regulatory domain" and contains generic settings. If this cannot be unset, CRDA may be misconfigured.}}
 +
 
 +
However, setting the regdomain may not alter your settings. Some devices have a regdomain set in firmware/EEPROM, which dictates the limits of the device, meaning that setting regdomain in software [http://wiki.openwrt.org/doc/howto/wireless.utilities#iw can only increase restrictions], not decrease them. For example, a CN device could be set in software to the US regdomain, but because CN has an EIRP maximum of 20dBm, the device will not be able to transmit at the US maximum of 30dBm.
 +
 
 +
For example, to see if the regdomain is being set in firmware for an Atheros device:
 +
 
 +
$ dmesg | grep ath:
 +
 
 +
For other chipsets, it may help to search for "EEPROM", "regdomain", or simply the name of the device driver.
 +
 
 +
To see if your regdomain change has been successful, and to query the number of available channels and their allowed transmit power:
 +
 
 +
$ iw list | grep -A 15 Frequencies:
 +
 
 +
A more permanent configuration of the regdomain can be achieved through editing {{ic|/etc/conf.d/wireless-regdom}} and uncommenting the appropriate domain. {{ic|wpa_supplicant}} can also use a regdomain in the {{ic|1=country=}} line of {{ic|/etc/wpa_supplicant/wpa_supplicant.conf}}.
 +
 
 +
It is also possible to configure the [http://wireless.kernel.org/en/developers/Documentation/cfg80211 cfg80211] kernel module to use a specific regdomain by adding, for example, {{ic|1=options cfg80211 ieee80211_regdom=EU}} as [[Kernel_modules#Setting module options|module options]]. However, this is part of the [http://wireless.kernel.org/en/developers/Regulatory#The_ieee80211_regdom_module_parameter old regulatory implementation].
 +
 
 +
For further information, read the [http://wireless.kernel.org/en/developers/Regulatory/ wireless.kernel.org regulatory documentation].
 +
 
 +
=== 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  
 
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  
Line 497: Line 463:
 
  # journalctl -f  
 
  # journalctl -f  
  
 +
Frequently a wireless error is accompanied by a deauthentication with a particular reason code, for example: 
 +
wlan0: deauthenticating from XX:XX:XX:XX:XX:XX by local choice (reason=3)
 +
 +
Looking up [http://www.aboutcher.co.uk/2012/07/linux-wifi-deauthenticated-reason-codes/ the reason code] might give a first hint. Maybe it also helps you to look at the control message [https://wireless.wiki.kernel.org/en/developers/documentation/mac80211/auth-assoc-deauth flowchart], the journal messages will follow it.
 +
 
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.
 
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.
  
Line 507: Line 478:
 
* 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 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:
+
* 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|power saving]] features (specify {{ic|off}} instead of {{ic|on}}).
 
+
# 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:
 
* 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:
Line 517: Line 486:
 
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.
 
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 ===
+
=== Valid IP address but cannot resolve host ===
  
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.
+
If you are on a public wireless network that may have a [[wikipedia:Captive_portal|captive portal]], make sure to query an HTTP page (not an HTTPS page) from your web browser, as some captive portals only redirect HTTP. If this is not the issue, it may be necessary to remove any custom DNS servers from [[resolv.conf]].
  
==== Lowering the rate ====
+
=== Setting RTS and fragmentation thresholds ===
  
Try setting lower rate, for example 5.5M:
+
Wireless hardware disables RTS and fragmentation by default. These are two different methods of increasing throughput at the expense of bandwidth (i.e. reliability at the expense of speed). These are useful in environments with wireless noise or many adjacent access points, which may create interference leading to timeouts or failing connections.  
  
# iwconfig wlan0 rate 5.5M auto
+
Packet fragmentation improves throughput by splitting up packets with size exceeding the fragmentation threshold. The maximum value (2346) effectively disables fragmentation since no packet can exceed it. The minimum value (256) maximizes throughput, but may carry a significant bandwidth cost.
  
Fixed option should ensure that the driver does not change the rate on its own, thus making the connection a bit more stable:
+
# iw phy0 set frag 512
  
# iwconfig wlan0 rate 5.5M fixed
+
[[Wikipedia:IEEE 802.11 RTS/CTS|RTS]] improves throughput by performing a handshake with the access point before transmitting packets with size exceeding the RTS threshold. The maximum threshold (2347) effectively disables RTS since no packet can exceed it. The minimum threshold (0) enables RTS for all packets, which is probably excessive for most situations.
  
==== Lowering the txpower ====
+
# iw phy0 set rts 500
  
You can try lowering the transmit power as well. This may save power as well:
+
{{Note|{{ic|phy0}} is the name of the wireless device as listed by {{ic|$ iw phy}}.}}
  
# iwconfig wlan0 txpower 5
+
=== Random disconnections ===
  
Valid settings are from {{ic|0}} to {{ic|20}}, {{ic|auto}} and {{ic|off}}.
+
==== Cause #1 ====
  
==== Setting rts and fragmentation thresholds ====
+
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|power saving]] features (specify {{ic|off}} instead of {{ic|on}}).
  
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.
+
If your card does not support enabling/disabling power save mode, check the BIOS for power management options. Disabling PCI-Express power management in the BIOS of a Lenovo W520 resolved this issue.
  
The minimum value for fragmentation value is 256 and maximum is 2346. In many windows drivers the maximum is the default value:
+
==== Cause #2 ====
  
# iwconfig wlan0 frag 2346
+
If you are experiencing frequent disconnections and dmesg shows messages such as
  
For rts minimum is 0, maximum is 2347. Once again windows drivers often use maximum as the default:
+
{{ic|1=ieee80211 phy0: wlan0: No probe response from AP xx:xx:xx:xx:xx:xx after 500ms, disconnecting}}
  
# iwconfig wlan0 rts 2347
+
try changing the channel bandwidth to {{ic|20MHz}} through your router's settings page.
  
=== Random disconnections ===
+
==== Cause #3 ====
  
==== Cause #1 ====
+
On some laptop models with hardware rfkill switches (e.g., Thinkpad X200 series), due to wear or bad design, the switch (or its connection to the mainboard) might become loose over time resulting in seemingly random hardblocks/disconnects when you accidentally touch the switch or move the laptop.
 +
There is no software solution to this, unless your switch is electrical and the BIOS offers the option to disable the switch.
 +
If your switch is mechanical (most are), there are lots of possible solutions, most of which aim to disable the switch: Soldering the contact point on the mainboard/wifi-card, glueing or blocking the switch, using a screw nut to tighten the switch or removing it altogether.
  
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:
+
==== Cause #4 ====
  
# iwconfig wlan0 power off
+
Another cause for frequent disconnects or a complete failure to connect may also be a sub-standard router, incomplete settings of the router, or interference by other wireless devices.
  
See [[Power saving]] for tips on how to make it permanent (just specify {{ic|off}} instead of {{ic|on}}).
+
To troubleshoot, first best try to connect to the router with no authentication.  
  
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.
+
If that works, enable WPA/WPA2 again but choose fixed and/or limited router settings. For example:
 
+
* If the router is considerably older than the wireless device you use for the client, test if it works with setting the router to one wireless mode
==== Cause #2 ====
+
* Disable mixed-mode authentication (e.g. only WPA2 with AES, or TKIP if the router is old)
 
+
* Try a fixed/free channel rather than "auto" channel (maybe the router next door is old and interfering)
If you are experiencing frequent disconnections and dmesg shows messages such as
+
* Disable {{ic|40Mhz}} channel bandwidth (lower throughput but less likely collisions)
 
+
* If the router has quality of service settings, check completeness of settings (e.g. Wi-Fi Multimedia (WMM) is part of optional QoS flow control. An erroneous router firmware may advertise its existence although the setting is not enabled)
{{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 ==
 
== Troubleshooting drivers and firmware ==
Line 583: Line 551:
 
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.
 
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].
+
A list of devices supported by the modules is available at the project's [http://rt2x00.serialmonkey.com/wiki/index.php/Hardware homepage]{{Dead link|2016|08|02}}.
  
 
; Additional notes
 
; Additional notes
Line 592: Line 560:
 
==== rt3090 ====
 
==== 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).
+
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 is 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.
+
The best way is to use the {{AUR|rt3090-dkms}}{{Broken package link|{{aur-mirror|rt3090-dkms}}}} driver. Make sure to [[blacklist]] the {{ic|rt2800pci}} module and setup the {{ic|rt3090sta}} module to [[Kernel modules#Automatic module handling|load]] at boot.
  
{{Note|This driver also works with rt3062 chipsets.}}
+
{{Note|This driver also works with rt3062 chipsets. Also the {{AUR|rt3090}}{{Broken package link|{{aur-mirror|rt3090}}}} package is not supported by the latest kernel and has been orphaned; {{AUR|rt3090-dkms}}{{Broken package link|{{aur-mirror|rt3090-dkms}}}} should be used instead. }}
  
 
==== rt3290 ====
 
==== rt3290 ====
Line 616: Line 584:
 
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 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.
+
{{AUR|8192cu-dkms}} includes many patches, try this if it does not work fine with the driver in kernel.
  
 
==== rtl8192e ====
 
==== rtl8192e ====
Line 634: Line 602:
 
==== rtl8188eu ====
 
==== 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.
+
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 Linux 3.12 the driver [http://lwn.net/Articles/564798/ has been moved] to kernel staging source tree. For older kernels use out-of-tree driver sources built with [[dkms]] - install {{AUR|8188eu-dkms}}. At the times of 3.15 kernel rtl8188eu driver is buggy and has many stability issues.
 +
 
 +
==== rtl8723ae/rtl8723be ====
 +
 
 +
The {{ic|rtl8723ae}} and {{ic|rtl8723be}} modules are included in the mainline Linux kernel.
 +
 
 +
Some users may encounter errors with powersave on this card. This is shown with occasional disconnects that are not recognized by high level network managers ([[netctl]], [[NetworkManager]]). This error can be confirmed by running {{ic|dmesg -w}} or {{ic|journalctl -f}} and looking for output related to powersave and the {{ic|rtl8723ae}}/{{ic|rtl8723be}} module. If you are having this issue, use the {{ic|1=fwlps=0}} kernel option, which should prevent the WiFi card from automatically sleeping and halting connection.
 +
 
 +
{{hc|/etc/modprobe.d/rtl8723ae.conf|2=
 +
options rtl8723ae fwlps=0
 +
}}
 +
or
 +
{{hc|/etc/modprobe.d/rtl8723be.conf|2=
 +
options rtl8723be fwlps=0
 +
}}
 +
 
 +
If you have very poor signal maybe your device has only one antenna connected and auto mode doesn't work. You can force the antenna with {{ic|1=ant_sel=1}} or {{ic|1=ant_sel=2}} kernel option.
  
 
=== Atheros ===
 
=== Atheros ===
Line 652: Line 636:
 
* http://wiki.debian.org/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.
+
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#Setting module options]] for details.
  
 
Some laptops may have problems with their wireless LED indicator flickering red and blue. To solve this problem, do:
 
Some laptops may have problems with their wireless LED indicator flickering red and blue. To solve this problem, do:
Line 667: Line 651:
 
* http://wiki.debian.org/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.
+
As of Linux 3.15.1, some users have been experiencing a decrease in bandwidth. In some cases this can fixed by editing {{ic|/etc/modprobe.d/ath9k.conf}} and adding the line:
An [https://lists.ath9k.org/mailman/listinfo/ath9k-devel ath9k mailing list] exists for support and development related discussions.
+
options ath9k nohwcrypt=1
  
===== ASUS =====
+
{{Note|Check with the command lsmod what module(-name) is in use and change it if named otherwise (e.g. ath9k_htc).}}
  
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.
+
In the unlikely event that you have stability issues that trouble you, you could try using the {{AUR|backports-patched}} package. An [https://lists.ath9k.org/mailman/listinfo/ath9k-devel ath9k mailing list] exists for support and development related discussions.
 +
 
 +
===== Power saving =====
 +
 
 +
Although [http://wireless.kernel.org/en/users/Documentation/dynamic-power-save Linux Wireless] says that dynamic power saving is enabled for Atheros ath9k single-chips newer than AR9280, for some devices (e.g. AR9285) {{Pkg|powertop}} might still report that power saving is disabled. In this case enable it manually.
 +
 
 +
On some devices (e.g. AR9285), enabling the power saving might result in the following error:
 +
 
 +
{{hc|# iw dev wlan0 set power_save on|
 +
command failed: Operation not supported (-95)
 +
}}
 +
 
 +
The solution is to set the {{ic|1=ps_enable=1}} option for the {{ic|ath9k}} module:
 +
 
 +
{{hc|/etc/modprobe.d/ath9k.conf|2=
 +
options ath9k ps_enable=1
 +
}}
  
 
=== Intel ===
 
=== Intel ===
Line 678: Line 678:
 
==== ipw2100 and ipw2200 ====
 
==== 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.
+
These modules are fully supported in the kernel, but they require additional firmware. Depending on which of the chipsets you have, [[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]]:
 
{{Tip|You may use the following [[Kernel modules#Setting module options|module options]]:
Line 689: Line 689:
 
[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.
 
[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.
+
[[udev]] should load the driver automatically, otherwise load {{ic|iwl3945}} or {{ic|iwl4965}} manually. See [[Kernel modules]] for details.
 +
 
 +
If you have problems connecting to networks in general or your link quality is very poor, try to disable 802.11n:
 +
 
 +
{{hc|/etc/modprobe.d/iwl4965.conf|2=
 +
options iwl4965 11n_disable=1
 +
}}
  
 
==== iwlwifi ====
 
==== iwlwifi ====
Line 695: Line 701:
 
[http://wireless.kernel.org/en/users/Drivers/iwlwifi iwlwifi] is the wireless driver for Intel's current wireless chips, such as 5100AGN, 5300AGN, and 5350AGN. See the [http://wireless.kernel.org/en/users/Drivers/iwlwifi#Supported_Devices full list of supported devices]. The firmware is included in the {{Pkg|linux-firmware}} package.
 
[http://wireless.kernel.org/en/users/Drivers/iwlwifi iwlwifi] is the wireless driver for Intel's current wireless chips, such as 5100AGN, 5300AGN, and 5350AGN. See the [http://wireless.kernel.org/en/users/Drivers/iwlwifi#Supported_Devices full list of supported devices]. The firmware is included in the {{Pkg|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:
+
If you have problems connecting to networks in general or your link quality is very poor, try to disable 802.11n, and perhaps also enable software encryption:
 +
 
 +
{{hc|/etc/modprobe.d/iwlwifi.conf|2=
 +
options iwlwifi 11n_disable=1
 +
options iwlwifi swcrypto=1
 +
}}
 +
 
 +
If you have a problem with slow uplink speed in 802.11n mode, for example 20Mbps, try to enable antenna aggregation:
 +
 
 +
{{hc|/etc/modprobe.d/iwlwifi.conf|2=
 +
options iwlwifi 11n_disable=8
 +
}}
 +
 
 +
Do not be confused with the option name, when the value is set to {{ic|8}} it does not disable anything but re-enables transmission antenna aggregation.[http://forums.gentoo.org/viewtopic-t-996692.html?sid=81bdfa435c089360bdfd9368fe0339a9] [https://bugzilla.kernel.org/show_bug.cgi?id=81571]
 +
 
 +
In case this does not work for you, you may try disabling [[Power saving#Network interfaces|power saving]] for your wireless adapter.
  
{{hc|/etc/modprobe.d/iwlwifi.conf|<nowiki>options iwlwifi 11n_disable=1
+
[http://ubuntuforums.org/showthread.php?t=2183486&p=12845473#post12845473 Some] have never gotten this to work. [http://ubuntuforums.org/showthread.php?t=2205733&p=12935783#post12935783 Others] found salvation by disabling N in their router settings after trying everything. This is known to have be the only solution on more than one occasion. The second link there mentions a 5ghz option that might be worth exploring.
options iwlwifi swcrypto=1</nowiki>}}
+
  
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:
+
{{Note|1=The {{pkg|linux-lts}}-3.14 kernel may take several minutes to load the firmware and make the wireless card ready for use. The issue is reported to be fixed in {{pkg|linux}}-3.17 kernel.[https://bbs.archlinux.org/viewtopic.php?id=190757]}}
{{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>}}
+
  
 
==== Disabling LED blink ====
 
==== Disabling LED blink ====
Line 735: Line 754:
 
This should be a part of the kernel package and be installed already.
 
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.
+
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, [[blacklist]] {{ic|orinoco_cs}} first.
  
 
==== prism54 ====
 
==== prism54 ====
Line 741: Line 760:
 
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.
 
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}}.}}
+
{{Note|There is also older, deprecated driver {{ic|prism54}}, which might conflict with the newer driver ({{ic|p54pci}} or {{ic|p54usb}}). Make sure to [[blacklist]] {{ic|prism54}}.}}
  
 
==== ACX100/111 ====
 
==== ACX100/111 ====
Line 753: Line 772:
 
==== zd1211rw ====
 
==== 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.
+
[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 [[install]] the firmware for the device, provided by the {{Pkg|zd1211-firmware}} package.
  
 
==== hostap_cs ====
 
==== hostap_cs ====
Line 759: Line 778:
 
[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.
 
[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.}}
+
{{Note|Make sure to [[blacklist]] the {{ic|orinico_cs}} driver, it may cause problems.}}
  
 
=== ndiswrapper ===
 
=== 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).
+
Ndiswrapper is a wrapper script that allows you to use some Windows drivers in Linux. You will need the {{ic|.inf}} and {{ic|.sys}} files from your Windows driver.  
 +
{{Warning|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}}.}}
 
{{Tip|If you need to extract these files from an {{ic|*.exe}} file, you can use {{Pkg|cabextract}}.}}
Line 769: Line 789:
 
Follow these steps to configure ndiswrapper.
 
Follow these steps to configure ndiswrapper.
  
1. Install the driver to {{ic|/etc/ndiswrapper/*}}
+
1. Install {{pkg|ndiswrapper-dkms}}
 +
 
 +
2. Install the driver to {{ic|/etc/ndiswrapper/*}}
 
  # ndiswrapper -i filename.inf
 
  # ndiswrapper -i filename.inf
2. List all installed drivers for ndiswrapper
+
 
 +
3. List all installed drivers for ndiswrapper
 
  $ ndiswrapper -l
 
  $ ndiswrapper -l
3. Write the following configuration file:
 
{{hc|/etc/modprobe.d/ndiswrapper.conf|
 
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.
+
4. Let ndiswrapper write its configuration in {{ic|/etc/modprobe.d/ndiswrapper.conf}}:
 +
# ndiswrapper -m
 +
# depmod -a
 +
 
 +
Now the ndiswrapper install is almost finished; follow the instructions on [[Kernel modules#Automatic module handling]] 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:
 
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:
Line 785: Line 807:
 
  # iwconfig
 
  # iwconfig
  
and ''wlan0'' should now exist. Check this page if you are having problems:
+
and ''wlan0'' should now exist. If you have problems, some help is available at:
[http://ndiswrapper.sourceforge.net/joomla/index.php?/component/option,com_openwiki/Itemid,33/id,installation/ Ndiswrapper installation wiki].
+
[http://sourceforge.net/p/ndiswrapper/ndiswrapper/HowTos/ ndiswrapper howto] and [http://sourceforge.net/p/ndiswrapper/ndiswrapper/FAQ/ ndiswrapper FAQ].
 
+
=== 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:
+
=== backports-patched ===
  
scripts/driver-select atheros
+
{{AUR|backports-patched}} provide drivers released on newer kernels backported for usage on older kernels. The project started since 2007 and was originally known as compat-wireless, evolved to compat-drivers and was recently renamed simply to backports.
  
Please read the package's [[PKGBUILD]] for any other possible modifications prior to compilation and installation.
+
If you are using old kernel and have wireless issue, drivers in this package may help.
  
 
== See also ==
 
== See also ==

Latest revision as of 17:10, 13 August 2016

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 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 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.

Note: Udev is not perfect. If the proper module is not loaded by udev on boot, simply 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 blacklist the unwanted module.
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 the lspci -k or lsusb -v command, depending on if the card is connected by PCI(e) or USB. You should see that some kernel driver is in use, for example:

$ lspci -k
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: If the card is a USB device, running dmesg | grep usbcore should give something like usbcore: registered new interface driver rtl8187 as output.

Also check the output of ip link command to see if a wireless interface (usually it starts with the letter "w", e.g. wlp2s1) was created. Then bring the interface up with ip link set interface up. For example, assuming the interface is wlan0:

# ip link set wlan0 up

If you get this error message: 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:

$ dmesg | grep firmware
[   7.148259] iwlwifi 0000:02:00.0: loaded firmware version 39.30.4.1 build 35138 op_mode iwldvm

If there is no relevant output, check the messages for the full output for the module you identified earlier (iwlwifi in this example) to identify the relevant message or further issues:

$ dmesg | grep iwlwifi
[   12.342694] iwlwifi 0000:02:00.0: irq 44 for MSI/MSI-X
[   12.353466] iwlwifi 0000:02:00.0: loaded firmware version 39.31.5.1 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:

Note that some vendors ship products that may contain different chip sets, even if the product identifier is the same. Only the usb-id (for USB devices) or pci-id (for PCI devices) is authoritative.

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 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.

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).
Tip:
  • 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.
  • If you anticipate to connect the machine to different wireless networks over time, a tool which provides its own connection management may be easier to handle.

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:

Management method Interface activation Wireless connection management
(/=alternatives)
Assigning IP address
(/=alternatives)
Manually managed,
with no or WEP encryption
ip iw / iwconfig ip / dhcpcd / dhclient / networkd
Manually managed,
with WPA or WPA2 PSK encryption
ip iw / iwconfig + wpa_supplicant ip / dhcpcd / dhclient / networkd
Automatically managed,
with network profiles support
netctl, Wicd, NetworkManager, etc.

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 ip from the iproute2 package.

You will need to install a basic set of tools for managing the wireless connection. Either:

  • iw - only supports the nl80211 (netlink) standard. It does not support the older WEXT (Wireless EXTentions) standard. If iw does not see your card, this may be the reason.
or
  • wireless_tools - currently deprecated, but still widely supported. Use this for modules using the WEXT standard.

For WPA/WPA2 encryption, you will also need:

The table below gives an overview of comparable commands for iw and wireless_tools (see iw replaces iwconfig for more examples). These user-space tools work extremely well and allow complete manual control of wireless connection.

Note:
  • iw and wpa_supplicant are provided on the installation medium.
  • Examples in this section assume that your wireless device interface is wlan0 and that you are connecting to your_essid wifi access point. Replace both accordingly. To find your wireless device interface, see #Getting some useful information.
  • Note that most of the commands have to be executed with 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.
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.
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 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:
$ iw dev
phy#0
	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:
$ iw dev wlan0 link
Not connected.

When connected to an AP, you will see something like:

$ iw dev wlan0 link
Connected to 12:34:56:78:9a:bc (on wlan0)
	SSID: MyESSID
	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:
$ 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

Tip: Usually this step is not required.

Some cards require that the kernel interface be activated before you can use iw or wireless_tools:

# ip link set wlan0 up
Note: If you get errors like 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:

# 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 UP in <BROADCAST,MULTICAST,UP,LOWER_UP> is what indicates the interface is up, not the later state DOWN.

Access point discovery

See what access points are available:

# iw dev wlan0 scan | less
Note: If it displays Interface does not 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 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 capability. If there is Privacy, for example capability: ESS Privacy ShortSlotTime (0x0411), then the network is protected somehow.
    • If you see an RSN information block, then the network is protected by Robust Security Network protocol, also known as WPA2.
    • If you see an WPA information block, then the network is protected by Wi-Fi Protected Access protocol.
    • In the RSN and 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 will 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 see neither RSN nor WPA blocks but there is Privacy, then WEP is used.

Operating mode

You might need to set the proper operating mode of the wireless card. More specifically, if you are going to connect an ad-hoc network, you need to set the operating mode to ibss:

# iw dev wlan0 set type ibss
Note: Changing the operating mode on some cards might require the wireless interface to be down (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 According to what you got from #Access point discovery, issue this command:
    # wpa_supplicant -D nl80211,wext -i wlan0 -c <(wpa_passphrase "your_SSID" "your_key")

If this does not work, you may need to adjust the options. If connected successfully, continue in a new terminal (or quit wpa_supplicant with Ctrl+c and add the -B switch to the above command to run it in the background). WPA supplicant contains more information on options and on how to create a permanent configuration file for the wireless access point.

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

for DHCP, or

# ip addr add 192.168.0.2/24 dev wlan0
# ip route add default via 192.168.0.1

for static IP addressing.

Tip: dhcpcd provides a hook, which can be enabled to automatically launch WPA supplicant on wireless interfaces.

Example

Here is a complete example of setting up a wireless network with WPA supplicant and DHCP.

# ip link set dev wlp13s1 up
# wpa_supplicant -B -i wlp13s1 -c /etc/wpa_supplicant/wpa_supplicant.conf
# dhcpcd wlp13s1

And then to close the connection, you can simply disable the interface:

# ip link set dev wlp13s1 down

For a static IP, you would replace the dhcpcd command with

# ip addr add 192.168.0.10/24 broadcast 192.168.0.255 dev wlp13s1
# ip route add default via 192.168.0.1

And before disabling the interface you would first flush the IP address and gateway:

# ip addr flush dev wlp13s1
# ip route flush dev wlp13s1

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.

Connection manager Network
profiles
support
Roaming
(auto connect dropped
or changed location)
PPP support
(e.g. 3G modem)
Official
GUI
Console tools
Connman Yes Yes Yes No connmanctl
netctl Yes Yes Yes No netctl,wifi-menu
NetworkManager Yes Yes Yes Yes nmcli,nmtui
Wicd Yes Yes No Yes wicd-curses
Wifi Radar Yes  ?  ? Yes wifi-radar

Connman

ConnMan is an alternative to NetworkManager and Wicd, designed to be light on resources making it ideal for netbooks, and other mobile devices. It is modular in design takes advandage of the dbus API and provides proper abstraction on top of wpa_supplicant.

See Connman.

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.

See Wicd.

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.

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 #Troubleshooting drivers and firmware.

Temporary internet access

If you have problematic hardware and need internet access to, for example, download some software or get help in forums, you can make use of Android's built-in feature for internet sharing via USB cable. See Android tethering#USB tethering for more information.

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 rfkill. Use rfkill to show the current status:

# 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 rfkill kernel module.

Hardware buttons to toggle wireless cards are handled by a vendor specific kernel module, frequently these are WMI modules. Particularly for very new hardware models, it happens that the model is not fully supported in the latest stable kernel yet. In this case it often helps to search the kernel bug tracker for information and report the model to the maintainer of the respective vendor kernel module, if it has not happened already.

See also: http://askubuntu.com/questions/62166/siocsifflags-operation-not-possible-due-to-rf-kill

Respecting the regulatory domain

The regulatory domain, or "regdomain", is used to reconfigure wireless drivers to make sure that wireless hardware usage complies with local laws set by the FCC, ETSI and other organizations. Regdomains use ISO 3166-1 alpha-2 country codes. For example, the regdomain of the United States would be "US", China would be "CN", etc.

Regdomains affect the availability of wireless channels. In the 2.4GHz band, the allowed channels are 1-11 for the US, 1-14 for Japan, and 1-13 for most of the rest of the world. In the 5GHz band, the rules for allowed channels are much more complex. In either case, consult this list of WLAN channels for more detailed information.

Regdomains also affect the limit on the effective isotropic radiated power (EIRP) from wireless devices. This is derived from transmit power/"tx power", and is measured in dBm/mBm (1dBm=100mBm) or mW (log scale). In the 2.4GHz band, the maximum is 30dBm in the US and Canada, 20dBm in most of Europe, and 20dB-30dBm for the rest of the world. In the 5GHz band, maximums are usually lower. Consult the wireless-regdb for more detailed information (EIRP dBm values are in the second set of brackets for each line).

Misconfiguring the regdomain can be useful - for example, by allowing use of an unused channel when other channels are crowded, or by allowing an increase in tx power to widen transmitter range. However, this is not recommended as it could break local laws and cause interference with other radio devices.

To configure the regdomain, install crda and reboot (to reload the cfg80211 module and all related drivers). Check the boot log to make sure that CRDA is being called by cfg80211:

$ dmesg | grep cfg80211

The current regdomain can be set to the United States with:

# iw reg set US

And queried with:

$ iw reg get
Note: Your device may be set to country "00", which is the "world regulatory domain" and contains generic settings. If this cannot be unset, CRDA may be misconfigured.

However, setting the regdomain may not alter your settings. Some devices have a regdomain set in firmware/EEPROM, which dictates the limits of the device, meaning that setting regdomain in software can only increase restrictions, not decrease them. For example, a CN device could be set in software to the US regdomain, but because CN has an EIRP maximum of 20dBm, the device will not be able to transmit at the US maximum of 30dBm.

For example, to see if the regdomain is being set in firmware for an Atheros device:

$ dmesg | grep ath:

For other chipsets, it may help to search for "EEPROM", "regdomain", or simply the name of the device driver.

To see if your regdomain change has been successful, and to query the number of available channels and their allowed transmit power:

$ iw list | grep -A 15 Frequencies:

A more permanent configuration of the regdomain can be achieved through editing /etc/conf.d/wireless-regdom and uncommenting the appropriate domain. wpa_supplicant can also use a regdomain in the country= line of /etc/wpa_supplicant/wpa_supplicant.conf.

It is also possible to configure the cfg80211 kernel module to use a specific regdomain by adding, for example, options cfg80211 ieee80211_regdom=EU as module options. However, this is part of the old regulatory implementation.

For further information, read the wireless.kernel.org regulatory documentation.

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 

Frequently a wireless error is accompanied by a deauthentication with a particular reason code, for example:

wlan0: deauthenticating from XX:XX:XX:XX:XX:XX by local choice (reason=3)

Looking up the reason code might give a first hint. Maybe it also helps you to look at the control message flowchart, the journal messages will follow it.

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 dhcpcd client, try installing and using dhclient instead. Do not forget to select dhclient as the primary DHCP client in your 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 (specify off instead of on).
  • If you get a timeout error due to a waiting for carrier problem, then you might have to set the channel mode to 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.

Valid IP address but cannot resolve host

If you are on a public wireless network that may have a captive portal, make sure to query an HTTP page (not an HTTPS page) from your web browser, as some captive portals only redirect HTTP. If this is not the issue, it may be necessary to remove any custom DNS servers from resolv.conf.

Setting RTS and fragmentation thresholds

Wireless hardware disables RTS and fragmentation by default. These are two different methods of increasing throughput at the expense of bandwidth (i.e. reliability at the expense of speed). These are useful in environments with wireless noise or many adjacent access points, which may create interference leading to timeouts or failing connections.

Packet fragmentation improves throughput by splitting up packets with size exceeding the fragmentation threshold. The maximum value (2346) effectively disables fragmentation since no packet can exceed it. The minimum value (256) maximizes throughput, but may carry a significant bandwidth cost.

# iw phy0 set frag 512

RTS improves throughput by performing a handshake with the access point before transmitting packets with size exceeding the RTS threshold. The maximum threshold (2347) effectively disables RTS since no packet can exceed it. The minimum threshold (0) enables RTS for all packets, which is probably excessive for most situations.

# iw phy0 set rts 500
Note: phy0 is the name of the wireless device as listed by $ iw phy.

Random disconnections

Cause #1

If dmesg says 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[1]. Try disabling the wireless card's power saving features (specify off instead of on).

If your card does not support enabling/disabling power save mode, 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

ieee80211 phy0: wlan0: No probe response from AP xx:xx:xx:xx:xx:xx after 500ms, disconnecting

try changing the channel bandwidth to 20MHz through your router's settings page.

Cause #3

On some laptop models with hardware rfkill switches (e.g., Thinkpad X200 series), due to wear or bad design, the switch (or its connection to the mainboard) might become loose over time resulting in seemingly random hardblocks/disconnects when you accidentally touch the switch or move the laptop. There is no software solution to this, unless your switch is electrical and the BIOS offers the option to disable the switch. If your switch is mechanical (most are), there are lots of possible solutions, most of which aim to disable the switch: Soldering the contact point on the mainboard/wifi-card, glueing or blocking the switch, using a screw nut to tighten the switch or removing it altogether.

Cause #4

Another cause for frequent disconnects or a complete failure to connect may also be a sub-standard router, incomplete settings of the router, or interference by other wireless devices.

To troubleshoot, first best try to connect to the router with no authentication.

If that works, enable WPA/WPA2 again but choose fixed and/or limited router settings. For example:

  • If the router is considerably older than the wireless device you use for the client, test if it works with setting the router to one wireless mode
  • Disable mixed-mode authentication (e.g. only WPA2 with AES, or TKIP if the router is old)
  • Try a fixed/free channel rather than "auto" channel (maybe the router next door is old and interfering)
  • Disable 40Mhz channel bandwidth (lower throughput but less likely collisions)
  • If the router has quality of service settings, check completeness of settings (e.g. Wi-Fi Multimedia (WMM) is part of optional QoS flow control. An erroneous router firmware may advertise its existence although the setting is not enabled)

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 rt2500, rt61, 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: rt2400pci, rt2500pci, rt2500usb, rt61pci or rt73usb which will autoload the respective rt2x00 modules too.

A list of devices supported by the modules is available at the project's homepage[dead link 2016-08-02].

Additional notes
  • Since kernel 3.0, rt2x00 includes also these drivers: rt2800pci, rt2800usb.
  • Since kernel 3.0, the staging drivers rt2860sta and rt2870sta are replaced by the mainline drivers rt2800pci and rt2800usb[2].
  • Some devices have a wide range of options that can be configured with iwpriv. These are documented in the source tarballs available from Ralink.

rt3090

For devices which are using the rt3090 chipset it should be possible to use rt2800pci driver, however, is not working with this chipset very well (e.g. sometimes it is not possible to use higher rate than 2Mb/s).

The best way is to use the rt3090-dkmsAUR[broken link: archived in aur-mirror] driver. Make sure to blacklist the rt2800pci module and setup the rt3090sta module to load at boot.

Note: This driver also works with rt3062 chipsets. Also the rt3090AUR[broken link: archived in aur-mirror] package is not supported by the latest kernel and has been orphaned; rt3090-dkmsAUR[broken link: archived in aur-mirror] should be used instead.

rt3290

The rt3290 chipset is recognised by the kernel rt2800pci module. However, some users experience problems and reverting to a patched Ralink driver seems to be beneficial in these cases.

rt3573

New chipset as of 2012. It may require proprietary drivers from Ralink. Different manufacturers use it, see the 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 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.

8192cu-dkmsAUR includes many patches, try this if it does not work fine with the driver in kernel.

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 Linux 3.12 the driver has been moved to kernel staging source tree. For older kernels use out-of-tree driver sources built with dkms - install 8188eu-dkmsAUR. At the times of 3.15 kernel rtl8188eu driver is buggy and has many stability issues.

rtl8723ae/rtl8723be

The rtl8723ae and rtl8723be modules are included in the mainline Linux kernel.

Some users may encounter errors with powersave on this card. This is shown with occasional disconnects that are not recognized by high level network managers (netctl, NetworkManager). This error can be confirmed by running dmesg -w or journalctl -f and looking for output related to powersave and the rtl8723ae/rtl8723be module. If you are having this issue, use the fwlps=0 kernel option, which should prevent the WiFi card from automatically sleeping and halting connection.

/etc/modprobe.d/rtl8723ae.conf
options rtl8723ae fwlps=0

or

/etc/modprobe.d/rtl8723be.conf
options rtl8723be fwlps=0

If you have very poor signal maybe your device has only one antenna connected and auto mode doesn't work. You can force the antenna with ant_sel=1 or ant_sel=2 kernel option.

Atheros

The MadWifi team currently maintains three different drivers for devices with Atheros chipset:

  • madwifi is an old, obsolete driver. Not present in Arch kernel since 2.6.39.1[3].
  • ath5k is newer driver, which replaces the madwifi driver. Currently a better choice for some chipsets, but not all chipsets are supported (see below)
  • 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 Linux Wireless documentation for details.

ath5k

External resources:

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 ath5k module with nohwcrypt=1 option. See Kernel modules#Setting module 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 this bug report.

ath9k

External resources:

As of Linux 3.15.1, some users have been experiencing a decrease in bandwidth. In some cases this can fixed by editing /etc/modprobe.d/ath9k.conf and adding the line:

options ath9k nohwcrypt=1
Note: Check with the command lsmod what module(-name) is in use and change it if named otherwise (e.g. ath9k_htc).

In the unlikely event that you have stability issues that trouble you, you could try using the backports-patchedAUR package. An ath9k mailing list exists for support and development related discussions.

Power saving

Although Linux Wireless says that dynamic power saving is enabled for Atheros ath9k single-chips newer than AR9280, for some devices (e.g. AR9285) powertop might still report that power saving is disabled. In this case enable it manually.

On some devices (e.g. AR9285), enabling the power saving might result in the following error:

# iw dev wlan0 set power_save on
command failed: Operation not supported (-95)

The solution is to set the ps_enable=1 option for the ath9k module:

/etc/modprobe.d/ath9k.conf
options ath9k ps_enable=1

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, install either ipw2100-fw or ipw2200-fw. Then reload the appropriate module.

Tip: You may use the following module options:
  • use the rtap_iface=1 option to enable the radiotap interface
  • use the led=1 option to enable a front LED indicating when the wireless is connected or not

iwlegacy

iwlegacy is the wireless driver for Intel's 3945 and 4965 wireless chips. The firmware is included in the linux-firmware package.

udev should load the driver automatically, otherwise load iwl3945 or iwl4965 manually. See Kernel modules for details.

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

/etc/modprobe.d/iwl4965.conf
options iwl4965 11n_disable=1

iwlwifi

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 perhaps also enable software encryption:

/etc/modprobe.d/iwlwifi.conf
options iwlwifi 11n_disable=1
options iwlwifi swcrypto=1

If you have a problem with slow uplink speed in 802.11n mode, for example 20Mbps, try to enable antenna aggregation:

/etc/modprobe.d/iwlwifi.conf
options iwlwifi 11n_disable=8

Do not be confused with the option name, when the value is set to 8 it does not disable anything but re-enables transmission antenna aggregation.[4] [5]

In case this does not work for you, you may try disabling power saving for your wireless adapter.

Some have never gotten this to work. Others found salvation by disabling N in their router settings after trying everything. This is known to have be the only solution on more than one occasion. The second link there mentions a 5ghz option that might be worth exploring.

Note: The linux-lts-3.14 kernel may take several minutes to load the firmware and make the wireless card ready for use. The issue is reported to be fixed in linux-3.17 kernel.[6]

Disabling LED blink

Note: This works with the iwlegacy and 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-tmpfiles:

/etc/tmpfiles.d/phy0-led.conf
w /sys/class/leds/phy0-led/trigger - - - - phy0radio

Run 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 /sys/class/leds/phy0-led, you may try to use the led_mode="1" module option. It should be valid for both iwlwifi and iwlegacy drivers.

Broadcom

See Broadcom wireless.

Other drivers/devices

Tenda w322u

Treat this Tenda card as an 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 wlags49_h2_cs driver instead of orinoco_cs and gain WPA support. To use the driver, blacklist orinoco_cs first.

prism54

The driver p54 is included in kernel, but you have to download the appropriate firmware for your card from this site and install it into the /usr/lib/firmware directory.

Note: There is also older, deprecated driver prism54, which might conflict with the newer driver (p54pci or p54usb). Make sure to blacklist prism54.

ACX100/111

Warning: The drivers for these devices are broken and do not work with newer kernel versions.

Packages: tiacx tiacx-firmware (deleted from official repositories and AUR)

See official wiki for details.

zd1211rw

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 [7] for a list of supported devices. You only need to install the firmware for the device, provided by the zd1211-firmware package.

hostap_cs

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 blacklist the orinico_cs driver, it may cause problems.

ndiswrapper

Ndiswrapper is a wrapper script that allows you to use some Windows drivers in Linux. You will need the .inf and .sys files from your Windows driver.

Warning: Be sure to use drivers appropriate to your architecture (x86 vs. x86_64).
Tip: If you need to extract these files from an *.exe file, you can use cabextract.

Follow these steps to configure ndiswrapper.

1. Install ndiswrapper-dkms

2. Install the driver to /etc/ndiswrapper/*

# ndiswrapper -i filename.inf

3. List all installed drivers for ndiswrapper

$ ndiswrapper -l

4. Let ndiswrapper write its configuration in /etc/modprobe.d/ndiswrapper.conf:

# ndiswrapper -m
# depmod -a

Now the ndiswrapper install is almost finished; follow the instructions on Kernel modules#Automatic module handling 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. If you have problems, some help is available at: ndiswrapper howto and ndiswrapper FAQ.

backports-patched

backports-patchedAUR provide drivers released on newer kernels backported for usage on older kernels. The project started since 2007 and was originally known as compat-wireless, evolved to compat-drivers and was recently renamed simply to backports.

If you are using old kernel and have wireless issue, drivers in this package may help.

See also