What is a limitation of firewalls?

Firewalls serve as a critical component of network security but have limitations in their operational scope. The reason “they cannot inspect traffic that does not pass through them” is correct is that firewalls operate at specific network boundaries, allowing or denying traffic according to set rules and configurations. If traffic bypasses the firewall—either through alternative routes or direct access—the firewall has no visibility into that traffic.

For example, if an internal attack occurs on a device already inside the network or if users access external services through unmonitored channels, the firewall will be ineffective in detecting or stopping that malicious activity. This limitation emphasizes the need for a multi-layered security approach, where additional security measures are implemented alongside firewalls to ensure comprehensive protection of network assets.

In contrast, other options highlight misunderstandings about the capabilities of firewalls:

• While firewalls can inspect many types of traffic, some encrypted traffic or traffic on non-standard ports may not be fully inspectable, which does not support the notion of being able to inspect all types of traffic.

• Firewalls typically do not block all incoming traffic; rather, they allow or deny traffic based on established rules. Therefore, stating they block all incoming traffic is an oversimplification.

• Finally, firewalls do