ZyXEL nbg-5715 Guia Do Utilizador

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 Appendix E Wireless LANs
NBG5715 User’s Guide
241
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.
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 or WPA2 and WEP are improved data encryption and user 
authentication.
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. 
If the AP or the wireless clients do not support WPA2, just use WPA or WPA-PSK depending on 
whether you have an external RADIUS server or not.
Select WEP only when the AP and/or wireless clients do not support WPA or WPA2. WEP is less 
secure than WPA or WPA2.
Encryption 
WPA improves data encryption by using Temporal Key Integrity Protocol (TKIP), Message Integrity 
Check (MIC) and IEEE 802.1x. WPA2 also uses TKIP when required for compatibility reasons, but 
offers stronger encryption than TKIP with Advanced Encryption Standard (AES) in the Counter 
mode with Cipher block chaining Message authentication code Protocol (CCMP).
TKIP uses 128-bit keys that are dynamically generated and distributed by the authentication server. 
AES (Advanced Encryption Standard) is a block cipher that uses a 256-bit mathematical algorithm 
Table 88   
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