WiFi¶
D-Link wireless N 150 (DWA-121) Pico USB adaptor install.
[kevin@raspberrypi ~]$ lsusb
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 001 Device 002: ID 0424:9512 Standard Microsystems Corp.
Bus 001 Device 003: ID 0424:ec00 Standard Microsystems Corp.
Bus 001 Device 004: ID 2001:3308 D-Link Corp. DWA-121 802.11n Wireless N 150 Pico Adapter [Realtek RTL8188CUS]
Note: If you don’t see it, make sure it is the only USB device plugged in because it takes a lot of power. Otherwise attach to a powered USB hub and you should be fine.
WPA2¶
First create a file with the following information, but substitute in the correct ssid and psk (with quotes around them) for your network.
[kevin@raspberrypi ~]$ more /etc/wpa_supplicant/wpa_supplicant.conf
ctrl_interface=/var/run/wpa_supplicant
ctrl_interface_group=0
ap_scan=2
network={
ssid="wireless access point name in quotes"
key_mgmt=WPA-PSK
proto=WPA2
pairwise=CCMP TKIP
group=CCMP TKIP
psk="pass phrase in quotes"
}
Note: The ssid is case sensitive!!
Network Setup¶
Next you will need to change your network interface for a static IP to:
[kevin@raspberrypi ~]$ more /etc/network/interfaces
auto lo
iface lo inet loopback
# dynamic interface
#iface eth0 inet dhcp
# static interface
iface eth0 inet static
address 192.168.1.120
netmask 255.255.255.0
gateway 192.168.1.1
auto wlan0
iface wlan0 inet static
address 192.168.1.121
wpa-conf /etc/wpa_supplicant/wpa_supplicant.conf
netmask 255.255.255.0
gateway 192.168.1.1
Note that the wifi interface (wlan0) points to the WPA config file from
above. Also there is an example dynamic interface commented out
(iface eth0 inet dhcp
) to show you how to use DHCP. The lo
is
the loopback interface, eth0 is the wired interface, with the wlan0
being the wireless interface. Also, the lines with auto
in them tell
linux to automatically start those interfaces during the bootup process.
Or if you are fine with DHCP determining all your IP addresses:
auto lo
iface lo inet loopback
iface eth0 inet dhcp
allow-hotplug wlan0
iface wlan0 inet manual
wpa-roam /etc/wpa_supplicant/wpa_supplicant.conf
iface default inet dhcp
Finally to get the wireless up and running, use ifup
to get things
started.
[kevin@raspberrypi ~]$ sudo ifup wlan0
ioctl[SIOCSIWAP]: Operation not permitted
ioctl[SIOCSIWENCODEEXT]: Invalid argument
ioctl[SIOCSIWENCODEEXT]: Invalid argument
These errors don’t seem to effect the wifi adaptor. You can double check
all is well by using iwconfig
.
[kevin@raspberrypi ~]$ iwconfig
lo no wireless extensions.
wlan0 IEEE 802.11bgn ESSID:"GC9J2" Nickname:"<WIFI@REALTEK>"
Mode:Managed Frequency:2.437 GHz Access Point: 00:7F:28:05:4D:D9
Bit Rate:150 Mb/s Sensitivity:0/0
Retry:off RTS thr:off Fragment thr:off
Power Management:off
Link Quality=100/100 Signal level=76/100 Noise level=0/100
Rx invalid nwid:0 Rx invalid crypt:0 Rx invalid frag:0
Tx excessive retries:0 Invalid misc:0 Missed beacon:0
eth0 no wireless extensions.
Looking at the wlan0 interface, it has a 150 Mb/s data rate (802.11n), and sees a signal strength of 76/100.
[kevin@raspberrypi ~]$ ifconfig wlan0
wlan0 Link encap:Ethernet HWaddr fc:75:16:04:96:5f
inet addr:192.168.1.121 Bcast:192.168.1.255 Mask:255.255.255.0
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:59222 errors:0 dropped:63403 overruns:0 frame:0
TX packets:11365 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:92009000 (87.7 MiB) TX bytes:1154992 (1.1 MiB)
Notice here a lot of dropped packets on the receive (RX).