Chapter 1 What’s New for FortiOS 5.2.1 : Firewall : Maximum Number of Available Virtual IPs Increased
  
Maximum Number of Available Virtual IPs Increased
The maximum limit of available virtual IPs has been increased on 1U FortiGate models (FortiGate-100 to 800 series) to 16,000 and on 2U FortiGate models (FortiGate-1000 to 3810 series) to 32,000.