ZyXEL Communications Corporation NWD271N Manual De Usuario

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Chapter 3 Wireless LANs
NWD271N User’s Guide
40
•  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 NWD271N 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.
3.3.1.2  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.
3.3.1.2.1  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 NWD271N supports EAP-TLS, EAP-TTLS (at the time of 
writing, TTLS is not available in Windows Vista) and EAP-PEAP. Refer to 
 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.
3.3.1.3  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.
If both an AP and the wireless clients support WPA2 and you have an external RADIUS 
server, use WPA2 for stronger data encryption. If you don't have an external RADIUS server, 
you should use WPA2-PSK (WPA2-Pre-Shared Key) that only requires a single (identical) 
password entered into each access point, wireless gateway and wireless client. As long as the 
passwords match, a wireless client will be granted access to a WLAN.