/etc/network/interfaces

# This file describes the network interfaces available on your system
# and how to activate them. For more information, see interfaces(5).

# The loopback network interface
auto lo
iface lo inet loopback

# The primary network interface
allow-hotplug eth0
iface eth0 inet dhcp

iface wlan0 inet dhcp
wpa-psk **********************
wpa-driver wext
wpa-key-mgmt WPA-PSK
wpa-proto WPA2
wpa-ssid OpenWrt

auto wlan0