ZyXEL p-660hwp Manual Do Utilizador

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Appendix B Wireless LANs
P-660HWP-Dx User’s Guide
42
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.
EAP-MD5 (Message-Digest Algorithm 5)
MD5 authentication is the simplest one-way authentication method. The authentication server 
sends a challenge to the wireless client. The wireless client ‘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. 
EAP-TLS (Transport Layer Security)
With EAP-TLS, digital certifications are needed by both the server and the wireless clients for 
mutual authentication. The server presents a certificate to the client. After validating the 
identity of the server, the client sends a different certificate to the server. The exchange of 
certificates is done in the open before a secured tunnel is created. This makes user identity 
vulnerable to passive attacks. A digital certificate is an electronic ID card that authenticates the 
sender’s identity. However, to implement EAP-TLS, you need a Certificate Authority (CA) to 
handle certificates, which imposes a management overhead. 
EAP-TTLS (Tunneled Transport Layer Service) 
EAP-TTLS is an extension of the EAP-TLS authentication that uses certificates for only the 
server-side authentications to establish a secure connection. Client authentication is then done 
by sending username and password through the secure connection, thus client identity is 
protected. For client authentication, EAP-TTLS supports EAP methods and legacy 
authentication methods such as PAP, CHAP, MS-CHAP and MS-CHAP v2. 
PEAP (Protected EAP)   
Like EAP-TTLS, server-side certificate authentication is used to establish a secure connection, 
then use simple username and password methods through the secured connection to 
authenticate the clients, thus hiding client identity. However, PEAP only supports EAP 
methods, such as EAP-MD5, EAP-MSCHAPv2 and EAP-GTC (EAP-Generic Token Card), 
for client authentication. EAP-GTC is implemented only by Cisco.
LEAP
LEAP (Lightweight Extensible Authentication Protocol) is a Cisco implementation of IEEE 
802.1x.