Appendix D Wireless LANs
VSG1435-B101 Series User’s Guide
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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.
Dynamic WEP Key Exchange
The AP maps a unique key that is generated with the RADIUS server. This key
expires when the wireless connection times out, disconnects or reauthentication
times out. A new WEP key is generated each time reauthentication is performed.
If this feature is enabled, it is not necessary to configure a default encryption key
in the wireless security configuration screen. You may still configure and store
keys, but they will not be used while dynamic WEP is enabled.
Note: EAP-MD5 cannot be used with Dynamic WEP Key Exchange
For added security, certificate-based authentications (EAP-TLS, EAP-TTLS and
PEAP) use dynamic keys for data encryption. They are often deployed in corporate
environments, but for public deployment, a simple user name and password pair
is more practical. The following table is a comparison of the features of
authentication types.
Table 128 Comparison of EAP Authentication Types
EAP-MD5 EAP-TLS EAP-TTLS PEAP LEAP
Mutual Authentication No Yes Yes Yes Yes
Certificate – Client No Yes Optional Optional No
Certificate – Server No Yes Yes Yes No
Dynamic Key Exchange No Yes Yes Yes Yes
Credential Integrity None Strong Strong Strong Moderate
Deployment Difficulty Easy Hard Moderate Moderate Moderate
Client Identity
Protection
No No Yes Yes No
