What is the function of a firewall?

A firewall serves as a security device designed to monitor and control network traffic based on predetermined security rules. Its primary function is to protect networks from unauthorized access, which is crucial for maintaining the confidentiality and integrity of data. Firewalls can either be hardware-based or software-based and act as a barrier between trusted internal networks and untrusted external networks, such as the internet.

By inspecting incoming and outgoing traffic and deciding which data packets to allow or deny, firewalls prevent malicious activities, unauthorized access attempts, and attachments that might contain malware from entering the network. This capability is vital for safeguarding sensitive information and ensuring that only legitimate users have access to specific resources within a network.

The other options represent functions that do occur in networking but do not specifically define what a firewall does. Managing network traffic can involve various devices and protocols, not just firewalls. Amplifying network signals is a role typically filled by repeaters or amplifiers. Connecting different networks is a function of routers rather than firewalls, which focus solely on security.