User Manual

Psion Teklogix 9160 Wireless Gateway User Manual 131
Chapter 13: Configuring Security
IEEE 802.1x
13.2.2.3 Static WEP With Transfer Key Indexes On Client Stations
Some Wireless client software (like Funk Odyssey) lets you configure multiple
WEP keys and set a transfer index on the client station, then you can specify differ-
ent keys to be used for station-to-AP transmissions. (The standard Windows wire-
less client software does not allow you to do this.)
To build on our example, using Funk Odyssey client software you could give each
of the clients WEP key 3 so that they can decode the AP transmissions with that key
and also give client 1 WEP key 1 and set this as its transfer key. You could then give
client 2 WEP key 2 and set this as its transfer key index.
The Figure 13.9 illustrates the dynamics of the AP and two client stations using
multiple WEP keys and a transfer key index.
Figure 13.9 Example Of Using Multiple WEP Keys And Transfer Key Index On Client Stations
13.2.3 IEEE 802.1x
IEEE 802.1x is the standard defining port-based authentication and infrastructure
for doing key management. Extensible Authentication Protocol (EAP) messages
sent over an IEEE 802.11 wireless network using a protocol called EAP Encapsula-
tion Over LANs (EAPOL). IEEE 802.1x provides dynamically-generated keys that
are periodically refreshed. An RC4 stream cipher is used to encrypt the frame body
and cyclic redundancy checking (CRC) of each 802.11 frame.
This mode requires the use of a RADIUS server to authenticate users, and configu-
ration of user accounts via the Cluster, User Management tab.
Access Point transmits to both stations with same WEP key
Client Station 1
Client Station 2
(e.g., WEP key 3)
W
E
P
k
e
y
3
WEP key 3
WEP key 2
WE
P
k
e
y
1
can decrypt WEP key 3
transmits in WEP key 1
can decrypt WEP key 3
transmits in WEP key 2