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IEEE 802.11 Authentication

Extensible Authentication Protocol-Transport Level Security (EAPTLS) is one type of authentication used for IEEE 802.11 networks. IEEE 802.11 defines two types of authentication: Open System Authentication and Shared Key Authentication

Open system authentication does not really provide authentication, only identification using the wireless adapter's MAC address. It is used when no authentication is required. Open system authentication is the default authentication algorithm and operates as follows:

  1. The authentication-initiating wireless client sends an IEEE 802.11 authentication management frame that contains its identity.
  1. The receiving wireless node checks the initiating station's identity and sends back an authentication verification frame.

With some wireless Access Points (APs) you can specify the MAC addresses of allowed wireless clients. However, this is not secure because the MAC address of a wireless client can be spoofed. By default, a Windows XP wireless client configured to perform open system authentication sends its MAC address as the identity.

Next: Shared Key Authentication