Docs/Drafts/WiFiNetworking

= WiFiNetworking =

Introduction
If your Wi-Fi networking is not working in Fedora Linux the clues which follow should assist you in repairing or circumventing the problem. An optimistic strategy to follow would be to: leads to wireless success. then  try one or more of the desktop wireless networking tools , again.
 * See if one or more of the desktop wireless networking tools
 * If needed,  try loading different firmware or a different driver ,
 * If needed,  try terminal command-line tools for wireless networking.

Wi-Fi is a licensed brand of the Wi-Fi Alliance, and is a commonly used term for wireless local area network products which observe the IEEE 802.11 standard (including its a, b, g, or.(expected) n amendments). A typical limit for the distance over which this wireless communication can be effective is several tens of meters or a few hundred feet.

If you are scanning for information before obtaining a system or obtaining a wireless network adapter for an existing system, you may wish to quickly read a short list of wireless adapters to avoid at: 

This collection of information focuses on the wireless networking management applications which are included in the Fedora Linux distribution. While each of these applications is also included in some other Linux or Unix distribution, they and the version of the kernel in the Fedora distribution are the main unique ingredients for wireless networking. Once one delves into command-line tools for wireless networking, there are few if any details which are unique to Fedora. So on these topics, especially, we settle for a brief outline or sketch, and supply links to selected bits of the large volume of wireless networking information available elsewhere. There is little benefit in duplicating such information here. If software and / or hardware change more so that some of the linked information becomes inaccurate or stale, then the link should be removed and the corrected information supplied directly here.

In an attempt to remain unbiased, the window manager environments are listed in alphabetical order, as are the individual applications which run in each environment. We do not attempt to rate the quality, completeness, or popularity of any wireless networking application. Instead, we hope to highlight some of the differentiating features which may be pertinent to an individual's choice for which application best fulfills their needs.

A goal in Fedora Collection 7 (presumably to be preserved or improved upon in subsequent releases) was to provide wireless networking support that "just works", transparently, with no additional user effort. Releases/FeatureRockSolidWireless

As the initial draft of this document is started, such robust wireless behavior has been partially implemented. The goals of this document are to provide: used to initiate and support wireless networking, state or debugging information to present in a bug report (with maybe an initial guess as to which set of developers may be the initial audience for the bug report). Realize that as drivers for networking hardware are updated, as new technology is introduced within the networking hardware, and other changes are made in the Linux system, you may witness a failure of your combination of wireless software and hardware for a combination that e.g.: In either case, the developers are unlikely to repair the failure unless you report your experience.
 * pointers toward user documentation for the applets / commands
 * help for you to recognize some of the various modes of failure, and
 * confidence for gathering what may be a useful collection of
 * has not previously functioned correctly, or
 * has operated flawlessly until a regression was made in a recent change.

We start with a field guide to the appearance of some of the Desktop (or Graphical User Interface) applications which may provide some status information about your network connectivity or offer some control or configuration choices.

NOTE BENE: Only ONE of these network management applications (e.g. NetworkManager, Network Monitor, K Manager installed on your system ] wireless access point signal strength (when the hover text is similar to e.g. Wireless network connection to 'YourNetworkName' (56%) when you are within range and authenticated with a wireless network) [[Image:Docs_Drafts_WiFiNetworking_file:////usr/share/icons/hicolor/22x22/apps/nm-signal-00.png, alt=0 bars ] [[Image:Docs_Drafts_WiFiNetworking_file:////usr/share/icons/hicolor/22x22/apps/nm-signal-25.png, alt=1 bars ]  [[Image:Docs_Drafts_WiFiNetworking_file:////usr/share/icons/hicolor/22x22/apps/nm-signal-50.png, alt=2 bars ]  [[Image:Docs_Drafts_WiFiNetworking_file:////usr/share/icons/hicolor/22x22/apps/nm-signal-75.png, alt=3 bars ]  [[Image:Docs_Drafts_WiFiNetworking_file:////usr/share/icons/hicolor/22x22/apps/nm-signal-100.png, alt=4 bar icon, if 'Network Manager Applet 0.6.5 you are reading the correct section of this document.
 * the 4 stair-step style bar graph of

How to Activate NetworkManager
So you wish to try using the NetworkManager applet, but it is not currently running? First stop or kill any other network management application that is running. Select the System entry in the top panel, select the Administration entry in the resulting menu, then select the Services entry in the cascaded menu.

On the Background Services tab of the Service Configuration application, in the left hand pane select the checkbox beside Network Manager running after future system restarts / reboots.

How to Deactivate NetworkManager
So you wish to try some other network management application than NetworkManager? Select the System entry in the top panel, select the Administration entry in the resulting menu, then select the Services entry in the cascaded menu.

On the Background Services tab of the Service Configuration application, in the left hand pane select the NetworkManager line, then select the Stop icon at the top of the pane. Also select File, Save Changes if you would like to leave NetworkManager inactive after future system restarts / reboots.

Partial Documentation for NetworkManager
Since as of yet there seems to be no compact collection of complete documentation for NetworkManager (beyond e.g. a Frequently Asked Questions page: and a little bit of other information on the GNOME project page:  ), here are some hints toward what behaviors to expect. While some people assert that NetworkManager labors with one goal, namely "to manage your network connection", some users perceive NetworkManager to wander among a complicated set of goals. Here, we do not attempt to describe in detail how this application interacts with your wired or Bluetooth networks. We attempt to remain focused on how NetworkManager may assist you with your goal of using your wireless network.

When you are within range of a [#Sec secured wireless network] , the icon may not reveal this fact if you are also still within range of another __unsecured__ wireless network, or are connected to a wired network. However, if you make a primary selection (with default left mouse button) on the Network Manager, $ sudo Network Manager''' is configured under Fedora different techniques are used [#NMActivate to activate NetworkManager] and [#NMDeactivate to deactivate NetworkManager].
 * restart it by entering the following command in a terminal:

Instead, while '''Network e.g. via:
 * selecting the System entry in the top panel,
 * selecting the Administration entry in the resulting menu, then
 * selecting the System Log entry in the cascaded menu.

Paste these selected lines, and It would be wise to edit this file to obscure portions of other information which should remain private, then Save this sanitized version of the file. The debug log in the file e.g.  should then be attached to your bug report at: 
 * Within the System Log Viewer application:
 * Select  in the left pane,
 * Select today's date (if needed) in the right pane,
 * Scroll down to the first Network Manager message.
 * Select Edit from the menu bar of System Log Viewer, then
 * select Copy from the resulting drop-down menu.
 * In your favorite text editor (e.g.,  ,  )
 * Save this file as e.g.
 * IP addresses,
 * ESSID names,
 * keys,
 * passphrases or

Network Monitor

 * Appearance of Network Monitor
 * How to Activate Network Monitor
 * Documentation for Network Monitor
 * Reporting Bugs in Network Monitor

Appearance of Network Monitor
Network Monitor runs by default on systems which were installed from the full DVD version of Fedora 7. Network Monitor is already running on your system if in the top panel (in some default desktop configurations, this is in the top panel near the right side, probably a little bit to the left of the User Name and the clock) there is a icon resembling one of: with hover text Network Connection: lo (for the local loopback device) with the rear screen in the icon blinking when your system receives data [[Image:Docs_Drafts_WiFiNetworking_file:////usr/share/icons/hicolor/48x48/apps/gnome-netstatus-rx.png,   width=64, height=48, alt=receiving icon, if Network Monitor installed on your system ]  and with the front screen in the icon blinking when your system sends data, and with hover text e.g. Network Connection: eth0, or the same icon with an icon of a white X on a red background in some conditions when the network cable is disconnected or your system is not connected to the wireless network, but with the same hover text. In addition, when when a wireless network device is selected immediately to the right of the terminal screens an additional portion of the icon: (which may appear merely as a diamond shape for a very weak signal), [[Image:Docs_Drafts_WiFiNetworking_file:////usr/share/icons/hicolor/48x48/apps/gnome-netstatus-75-100.png,    alt=4 bar icon, if Network Monitor installed on your system ]  and to the network, or red when your system is not connected to the network.
 * two overlapping terminal screens
 * two overlapping terminal screens
 * displays a vertical stacked bar graph of signal strength
 * changes color, with the bar graph being green when you are connected

The terminal screens in this icon appear to have a 16:9 aspect ratio. This icon (in some of its states) closely resembles the icon used by another program. To verify that this icon is the public face of Network Monitor (and not '''Network package is currently one of the 37 packages included in a default installation of the , you should not have to make any special effort to install this applet.)

Documentation for Network Monitor
The Network Monitor Manual can be opened by (default right mouse button), then
 * moving your mouse or pointing device over the Network Monitor icon,
 * selecting it with the secondary selection button
 * selecting Help from the resulting context menu.

Making a primary selection (default left button select) on the Network Monitor icon, or making a secondary selection (default right button select) on the icon then selecting Properties from the resulting context menu will open the Connection Properties: network_device dialog. This application will NOT automatically change the network device it monitors / displays / uses. But it does automatically update the list of devices available in the Name: textbox drop-down list of this Connection Properties: dialog. For example, when there is no other network device active, the list in the Name: textbox of the General tab of this properties dialog consists of: When another network device is or devices are active, this list may grow to include e.g. for a wireless network adapter)
 * lo (local loopback)
 * eth0
 * eth1 (... with a signal strength bar graph within the dialog
 * lo (local loopback)

Note that this dialog also shows e.g. network packet received and sent counts. This can provide a more compact way to view some of the information available from running System, Administration, System Monitor and watching the Network History portion of the Resources tab.

Wireless Networking Applications under KDE
This section describes applications which run in the KDE environment. If you are unsure whether you are currently using KDE, try to select the K icon (with flyover text of KMenu - Applications, tasks,and desktop sessions) for the Application menu in the bottom panel, and notice if the resulting menu is labelled something similar to KDE 3.5 along the left vertical edge. If it is, you are reading the correct section of this document.

If you are currently running in the environment of a window manager other than KDE, you may start KDE via (First, save any work you have in progress.): (if you know the password for another Username on this system). On the resulting graphical login screen, after selecting the Username and typing the Password: If KDE is not a choice in the next to last step above, you will need to install it first. If you are running GNOME, this can be done via Applications, Add/Remove Software. Within the resulting Package Manager application, on the Browse tab select Desktop Environments (in the left pane), and select KDE (K Desktop Environment) in the right pane. Also, select the List tab, and select ''kdenetwork-extras -... - Extras packages from KDEnetwork'' Use the Apply command button to start the process. Installing these packages will consume at least as much time as is required to download 230 MiB over your network connection.
 * System, Log Out, or
 * via the User Switcher in the notification area of the top panel
 * select Options (beneath the Username / Password textbox),
 * then select Select Session... from the context menu,
 * then select KDE, and
 * then select the Change Session command button,

KNetworkManager

 * Appearance of KNetworkManager
 * How to Activate KNetworkManager
 * Documentation for KNetworkManager
 * Reporting Bugs in KNetworkManager

Appearance of KNetworkManager
KNetwork Manager icon, and the presence of KNetwork Manager' applet, but it is not currently running? First stop or kill any other network management application that is running. Then select KMenu, select System, select KNetwork Manager via the KMmenu', and it appears nothing happens, open a terminal window and try again. That is, select KMenu, select System, select Terminal and in the resulting window titled "user@system:dir = Shell - Konsole" at the command prompt type: knetworkmanager (all lowercase). If the response is: org.freedesktop.Network Info already owned. then another user is already running this application. If you are on friendly terms with this other user, you may use KMenu, Switch User to select their existing session, and after supplying their password you can end their KNetwork Manager session. (? is there a safer / easier way than killing notification area applet  and Network Manager within the KDE Help Center (which is available via e.g. KMenu, Help). Given the heritage of the application as "a Network Manager icon, on the resulting menu select Help, and on the resulting cascaded menu select Report Bug.... This will allow you the opportunity to send email to bugs@kde.org with your bug report.

system-config-network
There are at least two paths through the menus when running KDE that lead to this same system-config-network utility. select System, then select Network Device Control from the cascaded menu. select Administration, then select Network from the cascaded menu.
 * Select KMenu,
 * Alternatively select KMenu,

KWiFiManager

 * Appearance of the KWiFiManager Applet
 * How to Activate KWiFiManager
 * Documentation for KWiFiManager
 * Reporting Bugs in KWiFiManager

Appearance of the KWiFiManager Applet
The K Fi Network Wi Manager application (e.g. by making a secondary selection (default right mouse button) on the 'K Fi by the   sudo'' utility, you will need to supply the root password to continue.}}

Within the resulting Package Manager application, on the List tab select ''kdenetwork-extras -... - Extras packages from KDEnetwork'' Use the Apply command button to start the installation. Once the installation is complete, you will need to log out and log back in, or use the User Switcher to start a new session in order to activate KWiFiManager as [#KWMActivate described above].

If you do not want to run the notification area applet, you can select KMenu, select Internet, select More Applications, then select KWiFiManager to start the application.

Documentation for KWiFiManager
From within KWiFiManager select Help, then select KWiFiManager Handbook to read thorough the documentation.

The same information is also available by selecting KMenu, selecting KDE Help, selecting Application Manuals, selecting Internet, selecting More Applications, then selecting KWiFiManager.

Note that the encryption status of a wireless connection is displayed only if you are [#Sudo running KWiFiManager as root]. Also, scanning for networks is likely to provide complete or consistent results only if 'KWiFi by the   sudo'' utility, you will need to supply the root password to continue.}}

will open a dialog titled Configure - KDE Control Module where one can configure encryption keys, etc. for connecting to a [#Sec secured wireless network].

Reporting Bugs in KWiFiManager
You can search for previously reported bugs, or report newly discovered bugs in KWiFiManager through Red Hat's bugzilla:  for the kdenetwork-extras component. You may also find information at the KWiFiManager project website: 

Might a Different Driver or Firmware Improve Matters?
You may be reading this section because you found that on your system at the moment the wireless networking components are not working and playing well together. In this situation it is possible that: (software loaded into your wireless network adapter), and / or (software loaded into your Fedora operating system) may lead to correctly operating wireless communications. Your manual efforts are required because firmware that is known to be necessary (or at least better than what is still loaded on your hardware), and and the one driver that works best for many users on other systems may not provide the best experience for all users.
 * finding and loading new firmware
 * finding and loading new drivers
 * in some cases licensing constraints bar Fedora from redistributing
 * for some hardware there are multiple drivers available,

The first step is to identify the wireless networking hardware in your system.

Since there are many different ways a wireless adapter can be packaged and built into or installed into your computer, there are different commands which may be needed to encourage your Fedora Linux software to compactly reveal to you what it knows about your wireless hardware. If you are running Gnome, If you are running KDE: In either case, type the following commands after the prompt (e.g. ). $ /sbin/lspci | grep 802 $ /sbin/lsusb $ /sbin/pccardctl ident If no relevant information seems to be provided in response to those queries, you may need to swim through the more voluminous output of $ /sbin/lspci
 * select the Applications entry in the top panel,
 * select the System Tools entry in the resulting menu, then
 * select the Terminal entry in the cascaded menu.
 * select KMenu,
 * select System,
 * select Terminal.

If you are willing to take the time to read several short paragraphs, scan the section "5 How to identify a card" in: 

Once you know an identification for your device, you may learn more about it by reading the appropriate section under:  or 

You may find even more interesting details about the changes and interactions with software for your device by searching. As an example, if your wireless adapter is built around a Broadcom chipset, you may benefit by reading postings such as: https://www.redhat.com/archives/fedora-list/2007-July/msg04468.html https://www.redhat.com/archives/fedora-list/2007-July/msg02069.html

Now you are armed with the knowledge of what wireless networking hardware you are attempting to use, and the knowledge (or at least someone else's opinions) of which software pieces are thought to be best to configure and control that hardware. You may now be led to: wireless networking hardware (This is a device-dependent step you will need to find documented in your reading elsewhere.) wireless networking hardware (This is a device-dependent procedure you will need to find documented in your reading elsewhere.) your Fedora Linux kernel to support this wireless hardware via: $ /sbin/lsmod which may entail downloading its source and compiling it for your kernel, see the linked section for some clues on how this may be done:  $ /sbin/modprobe -r OldModuleName ... (maybe several) $ /sbin/modprobe NewModuleName $ /sbin/service network reboot See the linked section for some additional clues. 
 * determine which version of firmware is loaded in your
 * install a different version of firmware in your
 * determine which driver is being loaded into
 * if you have been led to try a different driver,
 * you may need to find the new or different driver
 * you may need to remove a currently loaded module via:
 * you may wish to try loading a different module via:
 * and then make these changes known by:

Now, return to [#Gui the previous section] and see if your preferred (or any) desktop / GUI applications now provide a useful wireless network connection.

If even with another or the best known drivers and firmware the desktop / GUI applications do not provide a functional wireless network connection, you may wish to see if you can manually configure a useful connection by entering commands, as described in the following section.

Terminal Commandline Tools for Wireless Networking
Here is an outline of a sequence of commands you may be able to issue within a shell to configure and use your system's wireless networking capability. For example if you are running Gnome, If you are running KDE: In either case, type the following commands after the prompt (e.g. ). Once you find a sequence of commands with a set of proper parameters that tickles your wireless networking device into a working state, you probably wish to record this sequence of commands in a shell script to improve your chances for repeatable success.
 * select the Applications entry in the top panel,
 * select the System Tools entry in the resulting menu, then
 * select the Terminal entry in the cascaded menu.
 * select KMenu,
 * select System,
 * select Terminal.

It would be wise to Restart or Boot your system before beginning this procedure, as your previous attempts with other tools may have left the system in an interesting or inconsistent state.

Start by querying to find the device name for your wireless networking gear: $ /sbin/iwconfig In this example we will carry on using  as the wireless device name; your device name is likely to differ.

Next, configure the wireless interface to be up:

$ /usr/bin/sudo '/sbin/ifconfig eth1 up'

Are there signals from wireless routers or access points available in your current location? $ /sbin/iwlist eth1 scan

Depending upon the security mechanism in use for this wireless network, follow the appropriate one set of steps below:

1. If you recognize the name of your wireless network in this output, and  you are brave enough to be running it with no encryption , configure your wireless interface to associate with the device whose MAC address you supply, which you obtain from your prior knowledge of your network and verify from the response to the previous  command


 * }

$ /sbin/iwconfig eth1 ap BE:EF:FE:D0:A5:58

This is a bit safer than configuring an unsecured network with. e.g. $ /sbin/iwconfig eth1 essid "YourNetworkName" as it would be rather simple for someone to plant a new access point which impersonates at least the ESSID of your previously existing network, yet which mainly logs your keystrokes to capture passwords, etc.; yes, folks with no ethics may also spoof the MAC address of a previously existing network, but that usually requires a bit more effort.

1. If you recognize the name of your wireless network in this output, and  you are brave enough to be running it with the easily-compromised WEP encryption , you may configure your wireless interface to associate after supplying the encryption key.

$ /sbin/iwconfig eth1 key dead0beef1cafe2fed3abe4ba $ /sbin/iwconfig eth1 ap BE:EF:FE:D0:A5:58 This example illustrates configuring an encryption key for a network using a 128-bit WEP key, which should be expressed in 13 characters or 26 hex digits. If network is using a 40-bit WEP key, it should be expressed in exactly 5 characters or 10 hex digits.

1. If you recognize the name of your wireless network in this output, and your network uses Wi-Fi Protected Access or WPA encryption, there are a few additional configuration steps. You may wish to read portions from: $ info wpa_passphrase $ info wpa_supplicant.conf $ info wpa_supplicant To save you from the error-prone task of entering a 256-bit PSK (Pre-Shared Key) via your keyboard, you may wish to append the standard output of the command that generates the WPA PSK directly into the configuration file,

$ /usr/sbin/wpa_passphrase YourESSID >>/etc/wpa_supplicant/wpa_supplicant.conf Type your secret passphrase in plain text, then press Enter. Substitute the name of your network or its ESSID (Extended Service Set Identifier) in place of The passphrase has a length limit of 64 characters. Alternatively: $ /usr/sbin/wpa_passphrase YourESSID Type your secret passphrase in plain text, then press Enter. network={ ssid="YourESSID" psk=fc757c332c4d18a06da91a5670e25fab1b6b8b296e2da5a74029be7a72b8cde8 } and then Copy the 5 lines of output into the configuration file. Also, within if the network is using the weaker WPA (compared to WPA2) encryption the following lines should appear within this network stanza: key_mgmt=WPA-PSK proto=WPA while if the network is using the stronger WPA2 (compared to WPA) encryption the following lines should appear within this network stanza: key_mgmt=WPA-PSK proto=RSN

You may also need to alter the contents of another configuration file,

The INTERFACES line should refer to the name of your wireless device, and the DRIVERS line should be appropriate for your wireless hardware. You may wish to re-read a portion of: $ info wpa_supplicant It is possible that lines such as INTERFACES="-iwlan0" DRIVERS="-Dwext" may be appropriate (using the generic wireless extensions driver).

Now, you need to start the wpa_supplicant system service.

$ /sbin/chkconfig wpa_supplicant on

1. EAP ...

You may find some additional relevant wireless configuration instructions in: 

At this point, the wireless device specific configuration steps should be complete, and now you merely wish to configure this network link to be a useful link to the remainder of the network, just as if you were configuring a wired network connection. Namely, if your Internet Service Provider or network administrator has informed you to use the Dynamic Host Configuration Protocol (DHCP) try: $ dhclient eth1 (as above, substituting your wireless interface device name for eth1) and your system should now be in communication with the DHCP server, and soon allow you to communicate with the remainder of the network. Otherwise, you will probably need to configure: via the  and   commands again per information from your Internet Service Provider or network administrator.
 * a static IP address for your system,
 * the IP address(es) for your nameserver(s),
 * the gateway IP address, and
 * the netmask.

You may find some additional relevant network configuration instructions in: 

Diagnostic Steps
Recognize that your wireless network may encounter accidental competition or jamming or radio frequency interference from other devices such as: So if you can configure your wireless network device well enough to at least see a measure of the received signal strength it detects, you may gain enough information to focus on the real problem. Moving the location of your computer system or even the location of the wireless access point or router, or selecting a different channel (radio frequency used for communication) may reduce interference. Such physical activities may be simpler to implement than learning more about the software ingredients of a working wireless network connection.
 * portable cordless telephones,
 * baby monitor systems, and
 * maybe other electronic devices such as microwave ovens

While it may be a source of frustration as you attempt to configure and use your own network, take solace in the following for how it also slightly complicates life for those who would attempt to use your network without permission. In some situations, one cannot distinguish between: an incorrect key or passphrase (e.g. WEP when WPA is needed) Beware of your own fumble-fingered typing, and of keyboard keys in marginal condition which sometimes transmit zero or two events when you intended a single keypress. Unfortunately for you, but fortunately in general, no debug log or query will provide helpful insights such as You made a typographical error beginning at the 37th character of the passphrase.
 * attempting to associate with a secured network using
 * attempting to authenticate with the incorrect protocol

An interesting query is: $ /sbin/iwconfig which can list: counters of various packet transmission or reception events. The absence of a field that you believe to have been configured, or the presence of a surprising value in one of these fields may provide insight as to the cause of wireless network communication failures.
 * which 802.11 protocol (among a, b, g, and maybe someday n) is in use
 * the name or ESSID of the network with which your system has associated
 * the frequency (channel) used for wireless communication with this network
 * the MAC address of the network access point (or router)
 * the communication rate available with the current signal strength
 * the encryption key in use, if any
 * as well as several other measures of signal strength, and

If you have installed Network command: $ /sbin/ifconfig eth0     Link encap:Ethernet  HWaddr 00:01:30:68:48:59 (Yes, if your wireless adapter has not yet been successfully configured, it may not yet be displayed in this output; in any case, ensure that you note the MAC address for your wireless adapter, as there may be additional MAC addresses displayed for wired network adapters.), an address of the form of 12 hex digits, conventionally shown in 6 groups of 2 digits, separated by either spaces or colons ":", or Microsoft Windows can be run, viewing the response to the command > ipconfig /all issued in a command prompt window.
 * visual inspection of the adapter for a label containing
 * if the network adapter is installed on a system where

If you: have hardware and software support for WPA or WPA2 your network will be more secure using WPA2, which is more secure than WPA, which is more secure than any variety of WEP, which is better than an unsecured network with no encryption at all..
 * have administrative control over your wireless access point or router, and
 * all of the other devices which participate in this wireless network

LEAP

PEAP

EAP-TLS

Using the Command
Several of the wireless networking configuration or diagnostic applications or commands noted in this document require root or superuser privileges to run. If you are a mere user on your Fedora system, this may imply that resolving your wireless networking puzzles is the responsibility of the individual who is the root user or the superuser. Or it may imply that you would like to seek permission from that individual to be allowed to run some of these applications or commands to assist in resolving the networking problems.

As has been observed elsewhere, e.g. due to the lack of an audit trail and the increased security risks it is not wise for someone to merely tell you what the root password is.

Type $ info sudo or, if you prefer $ man sudo following the shell prompt (e.g. $) to learn more about the sudo (super user do) maintenance command.

Troubleshooting the regulatory domain restrictions
A regulatory domain is a region (such as USA, Europe, but also separate countries) where the same regulations for wireless networking apply. These regulations contain among other things also restriction what channels (frequencies) are allowed to be used for wireless in the specified domain. This can cause several problems as these restriction differ among many regulatory domains of course -- including allowed channels:

Note: this table is not kept to be up to date.

No wireless adapter should use channels which are not permitted in the regulatory domain. Therefore, since kernel 2.6.24, the default regulatory domain is set to be USA for drivers based on the mac80211 stack. Currently (05/2008) there is only one other choice available, namely the Japanese regulatory domain which can be set by adding the following line into you /etc/modprobe.conf file: options cfg80211 ieee80211_regdom="JP" This can be helpful also for other countries (e.g. if you come accross a network which uses channel 13 in Europe). Handling of regulatory problems is a known problem which should be solved in the future kernel development.

Sources:

http://www.cisco.com/en/US/docs/wireless/access_point/1200/vxworks/configuration/guide/bkscgaxa.html http://www.cisco.com/en/US/docs/wireless/wlan_adapter/cb21ag/admin/2.0/administration/guide/auappb.html https://bugzilla.redhat.com/show_bug.cgi?id=438756

Other Linux Wireless Networking Documentation
 ManagerFAQ