Chapter 15 Unified Threat Management for FortiOS 5.0 : Data leak prevention : Data leak prevention concepts : DLP filter
  
DLP filter
Each DLP sensor has one or more filters configured within it. Filters can examine traffic for known files using DLP fingerprints, for files of a particular type or name, for files larger than a specified size, for data matching a specified regular expression, or for traffic matching an advanced rule or compound rule.
You can configure the action taken when a match is detected. The actions include:
None
Log Only,
Block
Quarantine User,
Quarantine IP address
Quarantine Interface
Log Only is enabled by default.