WLAN not working rt2500

Nils Kassube kassube at gmx.net
Fri Dec 19 17:28:52 UTC 2008

Axel Heinrici wrote:
> I have a MSI S270 laptop branded "Medion". It seems I got everything
> working with kubuntu 8.04 except for WLAN.
> My problem is there is too much of information on the web and there are
> lots of ways how set the network up properly. It still didn't get the
> full picture of how wpasupplicant, networkmanager, native devices,
> avahi etc. are playing together. I am willing to read documentation but
> I still need some help to get a general overview.

OK, here is an overview how I understand it. It may be partly wrong but I 
hope others will correct me if necessary. At least it should get you 

Networkmanager selects the interface for your network connection. If you 
are connected with the wired interface that one will be used. Otherwise 
if the wireless interface is available, this will be used automatically 
if a known wireless network is found.

Knetworkmanager is the user interface for networkmanager so you don't need 
administrator privilege e.g. to select wireless networks.

Wpasupplicant is the application which handles the WPA/WPA2 encryption for 
your wireless interface. It has to be installed but it is controlled by 
networkmanager, so you don't need to configure it unless you want to have 
a special setup.

Avahi is a daemon which can provide interfaces with a configuration for 
local networks without DHCP server. It uses zeroconf addresses in the network. In theory it should not interfere with the other 
network settings. Well, in theory ...

> I have a linux router making connection to the internet and running a
> DHCP server. Connected to that I have a linksys access point (just
> accesspoint and not a router). The access point is using WPA-encryption
> which is running fine with windows and my symbian cell phone. Ethernet
> connection is also workig.
> Situation:
> ifconfig shows 5 interfaces : eth0, lo, wlan0, wlan0, wlan0:avahi and
> wmaster0.
> After I used the network-admin (KDEmenu->System->network) and put in
> the essid and the WPA passphrase a few packets are received and sended
> via wlan0. No packets are received or sent via wlan0:avahi nor
> wmaster0. DHCP is working for ethernet but not for WLAN.

Network-admin might be a problem. Please check that only the lo interface 
is mentioned in "/etc/network/interfaces". Interfaces mentioned in that 
file will be ignored by networkmanager. If other interfaces are mentioned 
there, please remove the entries (or make them comments with a "#" 
character at the beginning of each of those lines). BTW: You need root 
privilege to edit the file.

Right click the knetworkmanager icon. If no wireless networks are 
displayed, select options -> enable wireless networks. If wireless 
networks are shown, there should be one line with the name of your 
network. Click on that line and a new window should open which asks for 
the passphrase. If you can't see your wireless network, select "connect 
other wireless network". Then enter the network name, select the 
encryption type and enter the passphrase.

However not everybody is happy with networkmanager. If the procedure above 
doesn't work, it might worthwile to install Wicd [1] instead. Others can 
probably help you with that program if it doesn't work.


[1] <http://wicd.sourceforge.net/>

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