Rainbow Cybernuke - Connecting my opensuse 11 with LAN adapter Edimax Ew-7711UTn

bzidler writes "Some time ago I explained how you could use a Safecom adapter based on the Zydas 1211B chipset. I have given this one away and decided to buy a nicer one, the Edimax Ew-7711UTn. This one comes with a usb flexible extension, that can be useful. The adapter is supposed to be the smallest in the world. And indeed it is really small, but surprisingly good. You can find the specifications on :

http://www.edimax.co.uk/en/produce_detail.php?pd_id=280&pl1_id=1&pl2_id=44

One of the interesting feature (that I did not test) was the ability to use the 802.11n draft standard, allowing a connection at 150Mb/s, to a router such as the Netgear DGN2000.

This adapter uses the classic Ralink RT2870 driver which is included in the 2.6.27 kernel of the current Opensuse distribution. I plugged the mini adapter into a usb hub, and it was immediately identified.

# lsmod | grep 2870
rt2870sta             460004 1
usbcore               165892 6 rt2870sta,usb_storage,usbhid,uhci_hcd,ehci_hcd

Let's say that the SSID of my network is bznet, and that it is a configuration of a Netgear router using WPA-PSK/TKIP, and acting as a DHCP server as well.

At this point you can use YAST to configure the wireless network, or do it manually using wpa_passphrase. In this latest case you would do something like :

% /usr/sbin/wpa_passphrase bznet tuxisafriendlybird > ~/wifi/bznet.wpa
% cat bznet.wpa
network={
        ssid="bznet"
        #psk="tuxisafriendlybird"
        psk=13a5731a79463162eaf54e336e8b840e9d9d7cfdd660d572c0296844b4450a82
}

Under root the key can then be set up with : wpa_supplicant -i ra0 -c /home/bz/wifi/bznet.wpa -D wext &

But in my case I simply used YAST/Network Device/Network Stettings/Wireless. It generates the /var/run/wpa_supplicant-ra0.conf file with the ssid and psk information. It would then be just the passphrase used as key, and not the one generated with wpa_passphrase.

In /etc/sysconfig/network you must have a file ifcfg-ra0 in which you can find (among other lines) :
STARTMODE='hotplug'
WIRELESS_AUTH_MODE='psk'
WIRELESS_WPA_PSK='tuxisafriendlybird'

Check that wpa_supplicant is running :

# ps ax | grep wpa_supplicant | head -1
13545 ?        Ss     0:00 wpa_supplicant -ira0 -c/var/run/wpa_supplicant-ra0.conf -Dwext -P/var/run/wpa_supplicant/ra0.pid -B

Normally after this you should be ready to connect the wireless router. Try the next commands :

# iwlist scan
# dhclient ra0
# ifconfig -a

A problem you can encounter after disconnection the ethernet cable is that without a reboot your routing table may be confused between the ethernet connection and the wifi one :

# netstat -rn
Kernel IP routing table
Destination     Gateway         Genmask         Flags   MSS Window irtt Iface
192.168.0.0     0.0.0.0         255.255.255.0   U         0 0          0 eth0
192.168.0.0     0.0.0.0         255.255.255.0   U         0 0          0 ra0
169.254.0.0     0.0.0.0         255.255.0.0     U         0 0          0 eth0
127.0.0.0       0.0.0.0         255.0.0.0       U         0 0          0 lo
0.0.0.0         192.168.0.1     0.0.0.0         UG        0 0          0 eth0

You can use route del and route add to modify it or simply :

# ifdown eth0
# ifup ra0
# netstat -rn
Kernel IP routing table
Destination     Gateway         Genmask         Flags   MSS Window irtt Iface
192.168.0.0     0.0.0.0         255.255.255.0   U         0 0          0 ra0
127.0.0.0       0.0.0.0         255.0.0.0       U         0 0          0 lo
0.0.0.0         192.168.0.1     0.0.0.0         UG        0 0          0 ra0

The result shoud be a very good wifi link that may even improve with the latest drivers included in the 2.6.30 kernel.

# iwconfig
lo        no wireless extensions.

eth0      no wireless extensions.

vboxnet0 no wireless extensions.

ra0       RT2870 Wireless ESSID:"bznet" Nickname:"RT2870STA"
          Mode:Managed Frequency=2.462 GHz Access Point: 00:22:3F:56:64:B8
          Bit Rate=54 Mb/s
          RTS thr:off   Fragment thr:off
          Encryption key:53C9-D7B4-FA72-3D59-4AA6-915F-7D7C-FE2F
          Link Quality=100/100 Signal level:-23 dBm Noise level:-83 dBm
          Rx invalid nwid:0 Rx invalid crypt:0 Rx invalid frag:0
          Tx excessive retries:0 Invalid misc:0   Missed beacon:0

All in all it takes a few minutes to configure, no compilation of any source needed, and a micro adapter which is really cute and easy to use.

"