What Is a Wireless Network? 355
Something that has been popular for a while is the conversion of a DirecTV
or Dish network dish into a parabolic Wi-Fi antenna. With the availability of
these dishes on sites like eBay or Craigslist, it is possible for someone with
a minor monetary investment and basic skills to convert such a dish into
an effective long-range antenna.Wi-Fi Authentication Modes
When you are authenticating clients to a wireless network, two processes are available. The
first, known as open system authentication, is used in situations where you want to make
your network available to a wide range of clients. This type of authentication occurs when
an authentication frame is sent from a client to an access point. When the access point
receives the frame, it verifies its SSID, and if it’s correct the access point sends a verification
frame back to the client, allowing the connection to be made.
The second process is known as shared key authentication. In this process, each client
receives the key ahead of time and then can connect to the network as needed.
This is how shared key authentication works:
- The client sends an authentication request to the access point.
- The access point returns a challenge to the client.
- The client encrypts the challenge using the shared key it is configured with.
- The access point uses the same shared key to decrypt the challenge; if the responses
match, then the client is validated and is given access to the network.
Wireless Encryption Mechanisms
One of the big concerns with wireless networks is the fact that the data is vulnerable
when being transmitted over the air. Without proper protection, the transmitted data can
be sniffed and captured easily by an attacker. To prevent or at least mitigate this issue,
encryption is a layer of security that is included in most, if not all, wireless products.
The following are some of the more commonly used wireless encryption and
authentication protocols in use:
■ Wired Equivalent Privacy (WEP) is the oldest and arguably the weakest of the available
encryption protocols. The WEP standard was introduced as the initial solution to
wireless security but was quickly found to be flawed and highly vulnerable.■ Wi-Fi Protected Access (WPA) was the successor to WEP and was intended to address
many of the problems that plagued WEP. In many areas it succeeded and made for
a much tougher security protocol. WPA uses Temporal Key Integrity Protocol (TKIP),
message integrity code (MIC), and Advanced Encryption Standard (AES) encryption as
its main mechanism for securing information.■ WPA2 is the successor to WPA and was intended to address the problems with WPA.
WPA2 is much stronger and uses tougher encryption in the form of AES and CCMP