/etc/network/interfaces
-----------------------

You can now add extra statements to the iface sections of the files in
/etc/network/interfaces that are specific for wireless interfaces. They are of
the form:

    wireless-<function> <value>

After the interface is brought up, such a statement will result in the
execution of the following command:

    iwconfig <interface> <function> <value>

Note that there may be some drivers that only accept wireless configuration if
the interface is down. In that case, configuration from /etc/network/interfaces
may fail.

If you bring the interface down, then for each wireless-<function> statement
given it will execute a corresponding iwconfig command that reverts that
function back to sane defaults.  For example, if you specified a wireless-key,
if you run ifdown it will set the wireless key to "off".

If you want to specify a nick, nwid or essid with spaces in them, you must not
surround them with quotes.

To specify multiple keys the following statements are also available:

    wireless-key<number> <key>
    wireless-defaultkey <number>
    wireless-keymode restricted|open

To fine-tune power management the following statements are also available:

    wireless-powerperiod <period>
    wireless-powertimeout <timeout>

Example:

iface eth0 inet static
    address 192.168.1.2
    network 192.168.1.0
    netmask 255.255.255.0
    broadcast 192.168.1.255
    wireless-essid Home
    wireless-mode ad-hoc

Example of multiple keys:

    wireless-key1 0123-4567-89ab-cdef
    wireless-key2 12345678
    wireless-key3 s:password
    wireless-defaultkey 2
    wireless-keymode open