Wireless/Redundant Edge Services xl Module Management and Configuration Guide WS.02.xx and greater

4-61
Wireless Local Area Networks (WLANs)
Configuring a WLAN
b. Enter the preshared key.
As always, you should select a key that conforms to the highest
security standards. The longer the key and the more special charac-
ters it contains, the more secure it is. (The key must be at least 22
characters to withstand a brute force attack.)
You can enter the key in one of two ways:
– Select ASCII Passphrase, and then enter a password of from 8 to 63
characters. Users must enter the same characters to access the
WLAN.
– Select 256-bit key, and then enter the key manually in hexadecimal.
Enter 16 characters in each of the four fields.
5. If you want, check the Broadcast Key Rotation box.
Because all stations must use the same broadcast key, this key is clearly
more vulnerable to hackers than the per-session keys. Periodically chang-
ing the broadcast key helps to protect your WLAN.
By default, the Wireless Edge Services xl Module does not rotate the
broadcast key. However, if you enable the feature, the default rotation
period is every 7,200 seconds (two hours).
In the Update broadcast keys every field, you can enter any value from
60 seconds (one minute) through 86,400 seconds (one day). The shorter
the rotation period, the more secure, but also the more overhead added
by the key redistribution.
6. Click the OK button to apply your settings and close the WPA/WPA2 screen.
7. Click the OK button in the WLAN’s Edit screen to apply your settings.
Configuring Encryption for a WLAN that Uses MAC Authentication.
A WLAN that enforces MAC authentication to a network server can also
provide wireless encryption. In this case, a wireless user must pass two tests
to connect to the WLAN: the user’s station must pass MAC authentication, and
the user must enter the correct WEP or WPA/WPA2 key.
This section explains how to add encryption to a WLAN already configured
for RADIUS MAC authentication. See “MAC Authentication” on page 4-44 for
instructions on configuring the authentication.
After selecting MAC Authentication in a WLAN’s Edit screen, you have several
choices for which boxes in the Encryption section to check. Table 4-5 summa-
rizes these options and refers you to section that explains how to configure
the second security option.