What are the key differences between stateful and stateless firewalls?

Ask any question about Networking here... and get an instant response.

Post this Question & Answer:

What are the key differences between stateful and stateless firewalls?

Asked on Jan 17, 2026

Answer

Stateful and stateless firewalls differ primarily in how they handle and track network traffic. Stateful firewalls maintain a connection table to track active connections and make decisions based on the state of these connections, while stateless firewalls evaluate each packet independently without regard to connection state.

Example Concept: A stateful firewall inspects traffic flows and maintains a state table that tracks the state of active connections (e.g., TCP handshakes, UDP streams). It can make decisions based on the context of the traffic, such as allowing return traffic for an established connection. In contrast, a stateless firewall evaluates each packet in isolation, using predefined rules to allow or block traffic based solely on static criteria like source/destination IP addresses and ports, without considering the packet's relation to any ongoing session.

Additional Comment:

Stateful firewalls are generally more secure as they understand the context of the traffic.
Stateless firewalls are faster and require less memory since they do not track connection states.
Stateful firewalls are suitable for complex environments where traffic patterns are dynamic.
Stateless firewalls are often used for simple, high-speed filtering tasks.

✅ Answered with Networking best practices.

Ask any question about Networking here... and get an instant response.