High–level list of processes that affect packets

In general packets passing through a FortiGate unit can be affected by the following processes. This is a complete high-level list of all of the processes. Not all packets see all of these processes. The processes a packet encounters depends on the type of packet and on the FortiGate software and hardware configuration.

Ingress packet flow

• Network Interface
• TCP/IP stack
• DoS ACL
• DoS Policy
• IP integrity header checking
• IPsec VPN decryption

Admission Control

• Quarantine
• FortiHeartBeat
• User Authentication

Kernel

• Destination NAT
• Routing
• Stateful inspection/Policy
• Lookup/Session management
• Session Helpers
• User Authentication
• Device Identification
• SSL VPN
• Local Management Traffic

UTM/NGFW

• Flow-based inspection
• NTurbo
• IPSA
• Proxy-based inspection

Kernel

• Forwarding
• Source NAT (SNAT)

Egress packet flow

• IPsec VPN Encryption
• Botnet check
• Traffic shaping
• WAN Optimization
• TCP/IP stack
• Network Interface