Chapter 15 Unified Threat Management for FortiOS 5.0 : Web filter : Advanced web filter configurations : HTTP POST action
  
HTTP POST action
Select the action to take with HTTP POST traffic. HTTP POST is the command used by your browser when you send information, such as a form you have filled-out or a file you are uploading, to a web server.
The available actions include:
 
Normal
Allow use of the HTTP POST command as normal.
Comfort
Use client comforting to slowly send data to the web server as the FortiGate unit scans the file. Use this option to prevent a server time-out when scanning or other filtering is enabled for outgoing traffic.
The client comforting settings used are those defined in the Proxy Options profile selected in the security policy. For more information, see “Configuring client comforting”.
Block
Block the HTTP POST command. This will limit users from sending information and files to web sites.
When the post request is blocked, the FortiGate unit sends the http-post-block replacement message to the web browser attempting to use the command.