What are the primary functions of a firewall?

The primary function of a firewall is to monitor and control incoming and outgoing network traffic based on predefined security rules. Firewalls act as a barrier between trusted networks and untrusted networks, such as the internet, and they analyze traffic to determine whether to permit or block specific data packets. This enforcement of security policies helps protect the network from unauthorized access, attacks, and data breaches.

By establishing rules that specify which types of traffic are allowed and which are not, a firewall plays a crucial role in maintaining network security. For example, it can allow web traffic from specific sources while blocking potentially harmful data packets from entering the network. This functionality is essential in both personal and corporate environments, helping to safeguard sensitive information and ensuring that systems operate securely.

Other options do not encapsulate the central purpose of a firewall. Allowing only web traffic is too narrow of a focus since firewalls can control a wide range of traffic types. Encrypting data traffic pertains more to securing data transmission rather than controlling access, and storing and backing up data is not a function of firewalls but rather of storage devices or backup solutions.