What is the primary benefit of using a stateful firewall?

The primary benefit of using a stateful firewall is its ability to maintain session information. This means that it keeps track of the state of active connections and uses this context to determine whether incoming traffic is part of an established session or if it should be allowed through. By doing so, a stateful firewall can make more informed decisions about which packets to permit or block, based on the established rules for the traffic associated with these sessions.

This capability not only enhances security by recognizing and managing legitimate connections but also optimizes the handling of network traffic. For example, if a packet is received that does not correspond to any existing session, the firewall can deny it, effectively preventing unauthorized access that could occur if only individual packets were inspected.

A stateful firewall's session-tracking feature is a significant advancement over stateless firewalls, which treat each packet in isolation without understanding the context or history of traffic flows.