ZyXEL Wireless Access Point G1000 91-005-124003B Manual De Usuario

G-1000 User’s Guide

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Wireless LANs

• 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 appendix discusses some popular authentication types: EAP-MD5, EAP-TLS, EAP-
TTLS, PEAP and LEAP. 

The type of authentication you use depends on the RADIUS server or the AP. Consult your 
network administrator for more information.

MD5 authentication is the simplest one-way authentication method. The authentication server 
sends a challenge to the wireless station. The wireless station ‘proves’ that it knows the 
password by encrypting the password with the challenge and sends back the information. 
Password is not sent in plain text. 

However, MD5 authentication has some weaknesses. Since the authentication server needs to 
get the plaintext passwords, the passwords must be stored. Thus someone other than the 
authentication server may access the password file. In addition, it is possible to impersonate an 
authentication server as MD5 authentication method does not perform mutual authentication. 
Finally, MD5 authentication method does not support data encryption with dynamic session 
key. You must configure WEP encryption keys for data encryption.