Chapter 15 Unified Threat Management for FortiOS 5.0 : Client Reputation : Applying client reputation monitoring to your network
  
Applying client reputation monitoring to your network
Client reputation monitoring is applied to network traffic by going to Security Profiles > Client Reputation > Threat Level Definition turning on Client Reputation Tracking and selecting Apply.
You can then either change the client reputation profile used by your FortiGate unit or you can accept the default profile. The client reputation profile indicates how risky you consider different types of client behavior to be. See “Setting the client reputation profile/definition” for details.