ZyXEL Communications NWD217N, Руководство пользователя

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Chapter 3 Wireless LANs
NWD271N User’s Guide
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Figure 24 WPS: Example Network Step 3
3.4.4 Limitations of WPS
WPS has some limitations of which you should be aware.
• WPS works in Infrastructure networks only (where an AP and a wireless client
communicate). It does not work in Ad-Hoc networks (where there is no AP).
• When you use WPS, it works between two devices only. You cannot enroll multiple
devices simultaneously, you must enroll one after the other.
For instance, if you have two enrollees and one registrar you must set up the first enrollee
(by pressing the WPS button on the registrar and the first enrollee, for example), then
check that it successfully enrolled, then set up the second device in the same way.
• WPS works only with other WPS-enabled devices. However, you can still add non-WPS
devices to a network you already set up using WPS.
WPS works by automatically issuing a randomly-generated WPA-PSK or WPA2-PSK
pre-shared key from the registrar device to the enrollee devices (see
Section 4.4.1.2 on
page 55 for information on pre-shared keys). Whether the network uses WPA-PSK or
WPA2-PSK depends on the device. You can check the configuration interface of the
registrar device to discover the key the network is using (if the device supports this
feature). Then, you can enter the key into the non-WPS device and join the network as
normal (the non-WPS device must also support WPA-PSK or WPA2-PSK).
• When you use the PBC method, there is a short period (from the moment you press the
button on one device to the moment you press the button on the other device) when any
WPS-enabled device could join the network. This is because the registrar has no way of
identifying the “correct” enrollee, and cannot differentiate between your enrollee and a
rogue device. This is a possible way for a hacker to gain access to a network.
CLIENT 1 AP1
REGISTRAR
CLIENT 2
EXISTING CONNECTION
SEC
URIT
Y IN
FO
ENROLLEE
AP1
EX
IST
ING
CO
NN
EC
TIO
N