Chapter 1 What’s New for FortiOS 5.2.1 : New features in FortiOS 5.2 Patch 1 : Suppress probe response based on threshold in wireless controller vap
  
Suppress probe response based on threshold in wireless controller vap
The wireless controller vap supports probe response suppression (probe-resp-suppression) and probe response threshold (probe-resp-threshold).
Syntax
config wireless-controller vap
edit “SSID”
set probe-resp-suppression enable|disable
set probe-resp-threshold <value>
next
end
probe-resp-threshold range is [-20,-95]dBm, and the default is -80dBm if enabled