What is the primary function of a firewall?

What is the primary function of a firewall?

• A. Filters traffic
• B. Monitors for threats and alerts
• C. Encrypts data end-to-end
• D. Provides DNS resolution

Answer: (A)

Filtering traffic is the main function of a firewall. It acts as a gatekeeper at the network boundary, applying security rules to decide which packets are allowed through and which are blocked. By inspecting aspects like source and destination IPs, ports, protocols, and the state of connections, it enforces policy to prevent unauthorized access while still permitting legitimate communication, such as web traffic to an internal server. Encryption end-to-end is handled by TLS/SSL or VPN technologies, not by firewalls. Monitoring for threats and generating alerts is more the domain of IDS/IPS systems, though some firewalls include basic detection features; these are supplementary rather than the core purpose. DNS resolution is the job of a DNS server, not a firewall.

Filtering traffic is the main function of a firewall. It acts as a gatekeeper at the network boundary, applying security rules to decide which packets are allowed through and which are blocked. By inspecting aspects like source and destination IPs, ports, protocols, and the state of connections, it enforces policy to prevent unauthorized access while still permitting legitimate communication, such as web traffic to an internal server. Encryption end-to-end is handled by TLS/SSL or VPN technologies, not by firewalls. Monitoring for threats and generating alerts is more the domain of IDS/IPS systems, though some firewalls include basic detection features; these are supplementary rather than the core purpose. DNS resolution is the job of a DNS server, not a firewall.