How do wireless networks work?

As the name suggests, wireless networks,
sometimes called Wi-Fi, allow you to connect
to the internet without relying on wires. If
your home, office, airport or even local
coffee shop has a wireless connection, you
can access the network from anywhere that
is within the wireless area.
Wireless networks rely on radio waves rather
than wires to connect computers to the
internet. A transmitter, known as a wireless
access point or gateway, is wired into an
internet connection. This provides a "hot
spot" that transmits the connectivity over
radio waves.
Hotspots have identifying information,
including an item called an SSID, that allows
computers to locate them. Computers that
have a wireless card and have permission to
access the wireless frequency can take
advantage of the network connection. Some
computers may automatically identify open
wireless networks in a given area, while
others may require that you locate and
manually enter information such as the SSID.
What security threats are associated with
wireless networks?
Because wireless networks don't require a
wire between a computer and the internet
connection, it's possible for attackers who
are within range to hijack or intercept an
unprotected connection. A practice known as
war driving involoves individuals equipped
with a computer, wireless card and a GPS
device driving through areas in search of
wireless networks and identifying the specific
coordinates of a network location. This
information is then usually posted online.
What can you do to minimize the risks to
your wireless network?
Change default passwords.
Restrict access. Only allow authorized users
to access your network.
Encrypt data on your network. WEP (Wired
Equivalent Privacy) and WPA (Wi-Fi Protected
Access) both encrypt information on wireless
devices. Encrypting data prevents anyone
who might be able to access your network
from viewing your data.
Protect your SSID. To avoid outsiders easily
accessing your network, avoid publicizing
your SSID. Consult your user documentation
to see if you can change the default SSID to
make it more difficult to guess.
Install a firewall. While it's good practice to
install a firewall on your network, you
should also install a firewall directly on your
wireless devices. Attackers who can directly
tap into your wireless network may be able
to circumvent your network firewall- a host-
based firewall will add an extra layer of
protection.
Maintain your anti-virus software.