FortiGate Next Generation Firewall utilizes purpose-built security processors and threat intelligence security services from FortiGuard labs to deliver top-rated protection and high performance, including encrypted traffic.
Article Id 273204

This article describes the case when using DOS policies, and these ones are being triggered during the file transfer.


FileCatalyst is a Client/Server solution that allows file transfers over UDP(8000-8999).
This can trigger the UDP Flood threshold on the default settings of Fortigate's IPv4 DOS Policy causing FortiGate to drop the UDP sessions, causing the slow speed in the file transfer.


In this scenario, the uploads are done from outside, using a VIP, and the FileCatalyst is on the Firewall DMZ.

Scope FortiGate version 6.2.x, 6.4.x, 7.0.x, 7.2.x and above.
FileCatalyst uses the following ports for data transfers (8000-8999) TCP and UDP, and TCP port(21) to control connection, this is the most important ones.
For a complete list of ports, verify the link below:
  1. Create the service ports for this application:
  1. Now it is just necessary to create a new DOS policy on the top, for these ports and the server, and in this DOS policy, ensure UDP Flood is set to Disable or Monitor.
Always verify the DOS logs to be sure that there are not any drops for these ports or applications.