In the Firewall chain mode FFF refers to:

 In the Firewall chain mode FFF refers to all packets. Firewall chain mode is a feature that allows administrators to define how packets are processed by different firewall kernel modules in inbound and outbound directions. FFF is one of the predefined chain modes that applies all firewall kernel modules (Firewall, VPN, IPS, etc.) to all packets, regardless of their state or connection. This mode provides maximum security, but also consumes more CPU resources.