A technician is searching through a storage locker and finds a firewall. What is the purpose of this device?

The purpose of a firewall, like the one found by the technician in the storage locker, is to be placed between two or more networks and protect data and equipment from unauthorized access. A firewall is a network security device that monitors incoming and outgoing network traffic and decides whether to allow or block specific traffic based on a defined set of security rules. Its primary function is to establish a barrier between your internal network and external sources (such as the internet) to block malicious traffic like viruses and hackers.

The other options describe different types of network devices or functionalities:

• An all-in-one security appliance that includes IDS/IPS functionality as well as stateful firewall services typically refers to a more advanced type of firewall or a Unified Threat Management (UTM) system, which combines multiple security features in one device. While some firewalls have these capabilities, not all do.
• A device that connects multiple end devices and can be configured for VLANs and port security is typically a network switch. Switches are used to connect various devices on a local area network (LAN), like computers, and can segment traffic using VLANs.
• A device whose sole purpose is to connect end devices and to microsegment a LAN is also a description of a network switch, particularly focusing on its role in managing traffic within a LAN.