WESM zl Management and Configuration Guide WT.01.28 and greater

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Wireless Local Area Networks (WLANs)
Configuring a WLAN
Enabling Closed System Operations
Wireless stations have two ways that they can discover the SSID for a WLAN:
■ RPs send beacons that include the SSID for the WLAN. All wireless stations
listen for beacons.
■ RPs answer probes from stations requesting the RP to send all SSIDs that it
supports.
RPs can only beacon the SSIDs for the four primary WLANs (with normal
configuration, WLANs 1 through 4). This second option allows some wireless
stations to automatically discover the SSID for the other WLANs as well.
To configure a WLAN to operate truly in closed system—that is prevent wireless
stations from discovering the WLAN’s SSID—you must disable both of the functions
described above.
In the past, organizations have used closed system as a rudimentary security measure.
However, widely available wireless sniffer software can detect SSIDs in management
frames with already associated stations. Therefore, closed system deters only the
most casual of unauthorized users. For true security, enable authentication and
encryption as described in “Configuring Security Options” on page 4-33.
To configure a WLAN to operate in closed system, complete these steps:
1. Access the Edit screen for the WLAN:
a. Select Network Setup > WLAN Setup and click the Configuration tab.
b. Select the WLAN and click the Edit button. The Edit screen is displayed.