Firewalls are network security devices that monitor and control incoming and outgoing network traffic based on predetermined security rules. They act as barriers between trusted internal networks and untrusted external networks.
Types of firewalls:
Packet filtering firewalls: Examine individual packets and allow/deny based on source/destination IP, ports, and protocols. Fast but limited in functionality.
Stateful inspection firewalls: Track connection states and make decisions based on traffic context. They remember established connections and allow related return traffic.
Application layer firewalls (Proxy firewalls): Operate at the application layer, inspecting the actual content of communications. Can block specific applications or content types.
Next-generation firewalls (NGFW): Combine traditional firewall capabilities with additional features like intrusion prevention, application awareness, and deep packet inspection.
Web application firewalls (WAF): Specifically designed to protect web applications from attacks like SQL injection and cross-site scripting.
Firewalls use rule sets to determine actions (allow, deny, log) and are typically configured with a default-deny policy for maximum security.
This answer doesn't lend itself to a diagram - it reads best . No credits were charged.
The model's verdict: “”
The interactive diagram is below the answer - jump to diagram ↓
This answer is explained by a shared concept diagram - open →