What does a firewall primarily protect against?

A firewall primarily protects against network penetration, which refers to unauthorized access attempts to a network from external sources. Firewalls act as a barrier between a trusted internal network and untrusted external networks, such as the internet. They monitor and filter incoming and outgoing traffic based on predetermined security rules. By blocking or allowing traffic based on these rules, firewalls help to prevent unauthorized access to sensitive data and resources within the network.

This protective mechanism is essential for maintaining the integrity and confidentiality of the information stored and transmitted over a network. While other options like insider attacks, unsecured physical access, and data corruption are also important security concerns, they typically require different security measures beyond what a firewall is designed to do. For instance, combating insider attacks may involve user behavior monitoring and access controls, while protecting against unsecured physical access involves physical security measures such as locks or surveillance. Data corruption can result from various factors, including software bugs or malicious actions, requiring other forms of protection like data integrity checks or backup solutions.