🛡️ Palo Alto Firewall – How Every Packet Passes Through Step by Step

If you’re stepping into the world of Network Security, you must understand that Palo Alto is not just a traditional firewall — it’s a real Security Brain that protects the network from threats before they reach their destination.
🧩 Packet Flow Inside Palo Alto Firewall
1️⃣ Ingress – Packet Entry
The packet arrives at the firewall, whether from the Internet, branch offices, or internal users.
Every new packet is registered so the firewall can handle it correctly.
2️⃣ Decryption & Decoding – Decrypting and Understanding the Packet
If the packet is encrypted (HTTPS / VPN), the firewall decrypts it to inspect the content.
Then it analyzes:
Source & Destination IP
Port
Protocol
Application
3️⃣ Policy Lookup – Policy Matching
The firewall checks the packet against configured security policies: ✔ Who is allowed?
✔ Who is blocked?
✔ Does App Control or URL Filtering apply?
4️⃣ Session Creation / Lookup – Session Handling
If it’s a new packet → a new session is created.
If it belongs to an existing session → it continues under the same rules.
5️⃣ Content Inspection – Deep Content Inspection
✔ Antivirus / Anti-Spyware
✔ Threat Prevention
✔ File Blocking
✔ URL Filtering
Any malware or threat is detected and blocked before reaching the network.
6️⃣ Forwarding – Packet Forwarding
✔ If safe → forwarded to the destination (Data Center, Branch Office, or Internet).
✖ If not allowed → DROP
💡 Conclusion
Palo Alto Firewall = Intelligent protection for every part of the network:
Internet | Branches | Data Centers | Users
Every packet passes through 6 smart security stages, which makes Palo Alto one of the strongest NGFW solutions in the market