Life of Packet :

Life of packet

Exemple d'une connexion client/server :

The following example illustrates the flow of a packet of a client/web server connection with authentication and FortiGuard URL and antivirus filtering.
This example includes the following steps:

Initiating connection from client to web server

  1. Client sends packet to web server.
  2. Packet intercepted by FortiGate unit interface. 2.1 Link level CRC and packet size checking. If the size is correct, the packet continues, otherwise it is dropped.
  3. DoS sensor - checks are done to ensure the sender is valid and not attempting a denial of service attack.
  4. IP integrity header checking, verifying the IP header length, version and checksums.
  5. Next hop route
  6. Policy lookup
  7. User authentication
  8. Proxy inspection 8.1 Web Filtering 8.2 FortiGuard Web Filtering URL lookup 8.3 Antivirus scanning
  9. Source NAT
  10. Routing
  11. Interface transmission to network
  12. Packet forwarded to web server

Response from web server

  1. Web Server sends response packet to client.
  2. Packet intercepted by FortiGate unit interface 2.1 Link level CRC and packet size checking.
  3. IP integrity header checking.
  4. DoS sensor.
  5. Proxy inspection 5.1 Antivirus scanning.
  6. Source NAT.
  7. Stateful Policy Engine 7.1 Session Tracking
  8. Next hop route
  9. Interface transmission to network
  10. Packet returns to client

En image

Client server connection

Annexes :

FortiOS Handbook - Life of Packet