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Chapter 2 Wireless LANs
NWD-270N User’s Guide
20
2.3.1.1.2 Authentication Type
The IEEE 802.11b/g standard describes a simple authentication method between the wireless
stations and AP. Three authentication types are defined: Auto, Open and Shared.
• Open mode is implemented for ease-of-use and when security is not an issue. The
wireless station and the AP or peer computer do not share a secret key. Thus the wireless
stations can associate with any AP or peer computer and listen to any transmitted data that
is not encrypted.
• Shared mode involves a shared secret key to authenticate the wireless station to the AP or
peer computer. This requires you to enable the wireless LAN security and use same
settings on both the wireless station and the AP or peer computer.
• Auto authentication mode allows the NWD-270N to switch between the open system and
shared key modes automatically. Use the auto mode if you do not know the authentication
mode of the other wireless stations.
2.3.1.2 IEEE 802.1x
The IEEE 802.1x standard outlines enhanced security methods for both the authentication of
wireless stations and encryption key management. Authentication can be done using an
external RADIUS server.
2.3.1.2.1 EAP Authentication
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. The NWD-270N supports EAP-TLS, EAP-TTLS (at the time of
writing, TTLS is not available in Windows Vista) and EAP-PEAP. Refer to Appendix C on
page 71 for descriptions.
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). Certificates (also called digital IDs)
can be used to authenticate users and a CA issues certificates and guarantees the identity of
each certificate owner.
2.3.1.3 WPA and WPA2
Wi-Fi Protected Access (WPA) is a subset of the IEEE 802.11i standard. WPA2 (IEEE
802.11i) is a wireless security standard that defines stronger encryption, authentication and
key management than WPA.
Key differences between WPA(2) and WEP are improved data encryption and user
authentication.
Both WPA and WPA2 improve data encryption by using Temporal Key Integrity Protocol
(TKIP), Message Integrity Check (MIC) and IEEE 802.1x. WPA and WPA2 use Advanced
Encryption Standard (AES) in the Counter mode with Cipher block chaining Message
authentication code Protocol (CCMP) to offer stronger encryption than TKIP.