ZyXEL Communications Corporation P873HNUP51B Manuel D’Utilisation

 Chapter 7 Wireless

P-873HNUP-51B User’s Guide

Unauthorized wireless devices can still see the information that is sent in the wireless network, 
even if they cannot use the wireless network. Furthermore, there are ways for unauthorized 
wireless users to get a valid user name and password. Then, they can use that user name and 
password to use the wireless network.

Wireless networks can use encryption to protect the information that is sent in the wireless 
network. Encryption is like a secret code. If you do not know the secret code, you cannot 
understand the message.

The types of encryption you can choose depend on the type of authentication. (See 

Section 7.7.3.3 

on page 104

 for information about this.)

For example, if the wireless network has a RADIUS server, you can choose WPA or WPA2. If users 
do not log in to the wireless network, you can choose no encryption, Static WEP, WPA-PSK, or 
WPA2-PSK.

Usually, you should set up the strongest encryption that every device in the wireless network 
supports. For example, suppose you have a wireless network with the ZyXEL Device and you do not 
have a RADIUS server. Therefore, there is no authentication. Suppose the wireless network has two 
devices. Device A only supports WEP, and device B supports WEP and WPA. Therefore, you should 
set up Static WEP in the wireless network.

Note: It is recommended that wireless networks use WPA-PSK, WPA, or stronger 

encryption. The other types of encryption are better than none at all, but it is still 
possible for unauthorized wireless devices to figure out the original information 
pretty quickly.

When you select WPA2 or WPA2-PSK in your ZyXEL Device, you can also select an option (WPA
compatible) to support WPA as well. In this case, if some of the devices support WPA and some 
support WPA2, you should set up WPA2-PSK or WPA2 (depending on the type of wireless network 
login) and select the WPA compatible option in the ZyXEL Device.

Many types of encryption use a key to protect the information in the wireless network. The longer 
the key, the stronger the encryption. Every device in the wireless network must have the same key.

Because wireless networks are radio networks, their signals are subject to limitations of distance, 
interference and absorption.

Problems with distance occur when the two radios are too far apart. Problems with interference 
occur when other radio waves interrupt the data signal. Interference may come from other radio 

Table 22   Types of Encryption for Each Type of Authentication

No Security

WPA

Static WEP

WPA-PSK

WPA2-PSK

WPA2