Wireless LAN (Wireless Local area Network, WLAN, without cable local network) calls a "wireless" local radio network and mostly a standard of the IEEE 802.11-family is meant. A WLAN can be pursued in two kinds (modes) – in the infrastructure mode or in the ad hoc-mode.
In the infrastructure mode a base station, often a Wireless Access Point, is distinguished especially. He co-ordinates the single net knots. In the ad hoc-mode no station is particularly distinguished, but everybody is equivalent. Ad hoc-nets can be built up fast and without big expenditure. One does not plan that packages are handed on. It can seem that a physically centrally standing computer can reach the whole net, a computer in the edge area, nevertheless, only one part. Maximum 6 connections are possible for it in the ad hoc-mode.
The focus lies here on the infrastructure mode: one or several computers establish communication with a central Access Point.
To be able to be of use with Ubuntu WLAN, it is at first necessary to instal the WLAN map and then to configure suitably what should never happen without encoding.
More and more people use radio network works in her computer surroundings, because these have turned out extremely useful. Linux supports meanwhile originally a lot of WLAN maps. Still there are cases over and over again where the manufacturers of the chip sentences important for the installation to themselves deny her specifications to give change. But also in this case there is remedy. Thus nearly all WLAN maps can be installed under Linux.
Preparation
Basically the packages had to go at the company of a WLAN map
*
wireless-tools
*
wpasupplicant
instal become. They contain some tools to work on the settings of the map and to let indicate information about the WLAN (wireless-tools) and permit encoding on the newest state of the technology (wpasupplicant). One finds closer information about wireless-tools on this homepage {en}. The supported encoding technologies are explained on the wpasupplicant page {en} closer.
If it concerns a PCMCIA map (Cardbus), the package still has to go
*
pcmciautils
be installed.
Examination
WLAN maps use a whole series of different chip sentences. These are often supported by Ubuntu directly (just with notebooks). In the case nothing must be installed. So one should check first briefly in the terminal whether the map was recognised. With the order
iwconfig
if one receives a listing of all recognised network devices. Should the map not be performed here, an additional driver must be installed. In the successful case the result looks about thus:
user@station: ~ $ iwconfig
lo no wireless extensions.
ath0 IEEE 802.11 g unassociated ESSID
Mode:Managed Frequency:2.452 GHz Access Point: 00:14:BF:36:E2:B9
Bit Rate:12 Mb/page Tx-Power:18 dBm Sensitivity=0 / 3
Retry:off RTS thr:off fragment thr:off
Power Management:off
Link Quality=0 / 94 signals level =-68 dBm Noise level =-95 dBm
Rx disabled nwid:0 Rx disabled crypt:0 Rx disabled of frag:0
Tx excessive retries:0 Disabled misc:0 Missed beacon:0
eth0 no wireless extensions.
sit0 no wireless extensions.
The interfaces which are marked with no wireless extensions support obviously no WLAN. In this case is ath0 the recognised map. However, the WLAN interface can be called as well wlan0, eth1, etc. It is vital, in any case, that "Access Point" is recognised, if such is actively and in reach. In this case is to be done nothing else and it can become continued in the overview with the segment Configuration.
Configuration
After a successful installation and recognising the WLAN map this must be configured. This means as a rule, a connection with a Router / Access Point should be produced, so that one gets about that Internet access. In addition one must know which kind of connection of the Router offers. In the coarse are this WPA encoding, WEP encoding and no encoding. It is advised urgently against renouncing encoding (see segment Juridical). WEP encoding is cracked and should be used only if the Router supports no WPA encoding.
For an optimally functioning WLAN (which produces a connection already with the boat process) it is recommended to configure the connection by means of wpa supplicant. Here a list of all possibilities:
Wiki/Icons/background.png
With the help of a graphic surface
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Network manager can produce connections with all kinds of networks (also LAN)
*
Wifi radar supports WPA and WEP
*
Wicd is a graphic surface for wpa supplicant and an alternative to the Network manager.
Wiki/Icons/terminal.png
With the help of the terminal
wpa to furnish the WLAN supplicant - The momentary king's way. In this manner the new Upstart is also optimally used by Edgy (the connection breaks off, it is built up automatically anew).
wireless-tools - Offering general information about the WLAN (e.g., available nets) and allows WEP and uncoded connections to be based.
/etc/network/interfaces - The most important configuration file for the network (whether LAN or WLAN); here sooner or later one looks, in any case, purely. In this article her contents are explained.
