What is the difference between stateful and stateless firewall?

Question

Accepted Answer

**Stateful** — tracks connections. **Stateless** — filters packets individually.

**Stateful Firewall:**
- Tracks connection state.
- Knows connection context.
- More secure.
- Higher resource usage.

```
Stateful:
Connection: Client → Server (SYN)
Firewall: tracks this connection
Response: Server → Client (ACK)
Firewall: allows (part of tracked connection)
(Tracks state)
```

**Stateless Firewall:**
- Individual packets.
- No connection context.
- Faster.
- Less secure.

```
Stateless:
Packet 1: Allow (matches rule)
Packet 2: Allow (matches rule)
(Each packet independent)
```

**Key differences:**
- **Stateful** — tracks connections.
- **Stateless** — individual packets.
- **Stateful** — more secure.
- **Stateless** — faster.

Systems Analyst: What is the difference between stateful and stateless firewall?