ZyXEL Communications Prestige 662HW Series, User Manual

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Prestige 662HW Series User’s Guide
6-8 Wireless LAN Setup
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Access-Challenge
Sent by a RADIUS server requesting more information in order to allow access. The access
point sends a proper response from the user and then sends another Access-Request message.
The following types of RADIUS messages are exchanged between the access point and the RADIUS
server for user accounting:
•
Accounting-Request
Sent by the access point requesting accounting.
•
Accounting-Response
Sent by the RADIUS server to indicate that it has started or stopped accounting.
In order to ensure network security, the access point and the RADIUS server use a shared secret key,
which is a password, they both know. The key is not sent over the network. In addition to the shared
key, password information exchanged is also encrypted to protect the network from unauthorized
access.
6.6.3 EAP Authentication Overview
EAP (Extensible Authentication Protocol) is an authentication protocol that runs on top of the
IEEE802.1x transport mechanism in order to support multiple types of user authentication. By using
EAP to interact with an EAP-compatible RADIUS server, the access point helps a wireless station and
a RADIUS server perform authentication.
Figure 6-5 EAP Authentication
The details below provide a general description of how IEEE 802.1x EAP authentication works. For
an example list of EAP-MD5 authentication steps, see the appendix about IEEE 802.1x.
6.
The wireless station sends a “start” message to the Prestige.
7.
The Prestige sends a “request identity” message to the wireless station for identity information.
8.
The wireless station replies with identity information, including username and password.
9.
The RADIUS server checks the user information against its user profile database and determines
whether or not to authenticate the wireless station.
6.7 Introduction to WPA
Wi-Fi Protected Access (WPA) is a subset of the IEEE 802.11i security specification draft. Key
differences between WPA and WEP are user authentication and improved data encryption.
6.7.1 User Authentication
WPA applies IEEE 802.1x and Extensible Authentication Protocol (EAP) to authenticate wireless
clients using an external RADIUS database. You can’t use the Prestige’s Local User Database for