What is the primary function of a firewall in network security?

The primary function of a firewall in network security is to monitor outgoing and incoming traffic. A firewall acts as a barrier between a trusted internal network and untrusted external networks, such as the internet. It analyzes the packets of data that attempt to enter or leave the network, allowing or blocking them based on predetermined security rules. This capability is crucial for protecting sensitive information from unauthorized access and mitigating the risk of cyber threats, such as malware and intrusions.

The other options reflect functions that are not directly related to the role of a firewall. Amplifying network signals pertains to signal strength and transmission quality, which are dealt with by other networking equipment, such as repeaters or amplifiers. Encrypting data transmissions is related to securing the data itself rather than controlling access, typically handled by encryption protocols. Automatic data backup focuses on data preservation and recovery rather than on network security measures.