What do firewalls primarily protect against?

Firewalls primarily function as a barrier between a trusted internal network and untrusted external networks, such as the Internet. Their main purpose is to control incoming and outgoing network traffic based on predetermined security rules. By doing so, they are designed to protect against network intrusions and external threats, which could include unauthorized access, malicious attacks, and attempts to exploit vulnerabilities within the network.

The effectiveness of firewalls in mitigating these risks is rooted in their ability to monitor and filter traffic, ensuring that potentially harmful data packets or connection attempts are blocked. This capability makes them a crucial component of overall network security, as they help to preserve the integrity and confidentiality of the data within the network while allowing legitimate traffic to pass.

In contrast, while other options, such as internal data loss and phishing attacks, represent important security concerns, they are addressed through different security measures and controls. For instance, preventing internal data loss typically involves data loss prevention (DLP) technologies and internal policies, while combating phishing attacks requires user education, email filtering solutions, and other protective strategies tailored specifically for email communications. Malicious insider activity is also a concern that extends beyond what a firewall is designed to address, requiring monitoring and behavior analysis within the organization.