/etc/network/interfaces

# The loopback network interface
auto lo
iface lo inet loopback

# eth0 network interface
auto eth0
allow-hotplug eth0
iface eth0 inet dhcp
iface eth0 inet6 manual
    pre-down ip -6 addr flush dev $IFACE

# wlan0 network interface
auto wlan0
allow-hotplug wlan0
iface wlan0 inet dhcp
    wpa-ssid NOMEDELROUTER
    wpa-key-mgmt WPA-PSK
    wpa-psk LAMIAPASSWORD