Fortinet 5.0 Patch 6 - page 342

Fortinet 342 FortiWeb 5.0 Patch 6 Administration Guide
Real Browser
Enforcement
If you want to return a JavaScript to the client to test whether it is a
web browser or automated tool when it exceeds the rate limit,
enable this option. If either the client fails the test, or if it does not
return results before the Validation Timeout, FortiWeb will apply the
Action. If the client appears to be a web browser, FortiWeb will
allow the client to exceed the action. See also “Bot analysis” on
page 605.
Disable this option to apply the rate limit regardless of whether the
client is a web browser such as Firefox or an automated tool such
as wget.
Validation Timeout Enter the maximum amount of time that FortiWeb will wait for
results from the client for Real Browser Enforcement.
Setting name Description