ZyXEL nbg-5715 Guia Do Utilizador

 Appendix E Wireless LANs

NBG5715 User’s Guide

RADIUS is a simple package exchange in which your AP acts as a message relay between the 
wireless client and the network RADIUS server. 

The following types of RADIUS messages are exchanged between the access point and the RADIUS 
server for user authentication:

• Access-Request

Sent by an access point requesting authentication.

• Access-Reject

Sent by a RADIUS server rejecting access.

• Access-Accept

Sent by a RADIUS server allowing access. 

• 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. 

This section discusses some popular authentication types: EAP-MD5, EAP-TLS, EAP-TTLS, PEAP and 
LEAP. Your wireless LAN device may not support all authentication types. 

EAP (Extensible Authentication Protocol) is an authentication protocol that runs on top of the IEEE 
802.1x transport mechanism in order to support multiple types of user authentication. By using EAP 
to interact with an EAP-compatible RADIUS server, an access point helps a wireless station and a 
RADIUS server perform authentication. 

The type of authentication you use depends on the RADIUS server and an intermediary AP(s) that 
supports IEEE 802.1x. .

For EAP-TLS authentication type, you must first have a wired connection to the network and obtain 
the certificate(s) from a certificate authority (CA). A certificate (also called digital IDs) can be used 
to authenticate users and a CA issues certificates and guarantees the identity of each certificate 
owner.