Somehow I assumed it had something to do with the network manager. So I completely removed the Network Manager via
apt-get remove network-managerand configured my wlan interface (using instructions from a german ubuntu forum) manually editing /etc/network/interfaces:
iface eth1 inet dhcp wpa-conf /etc/wpa_supplicant/wpa_supplicant.conf auto eth1My wpa_supplicant.conf looks something like this:
ctrl_interface=/var/run/wpa_supplicant eapol_version=1 ap_scan=1 network={ ssid="YourWlanSSID" # scan_ssid=1 proto=WPA key_mgmt=WPA-PSK pairwise=TKIP group=TKIP psk=YourPSK }Note: I am using WPA encryption for my WLAN.
You can test your wpa_supplicant configuration using the following command:
sudo wpa_supplicant -i eth1 -D wext -c /etc/wpa_supplicant/wpa_supplicant.conf -dOption -i defines the network interface name of your WLAN card. Option -D declares the driver to use and option -c defines the wpa_supplicant configuration file.
After this I restarted my system and I got a working wlan connection to my Access Point.