Firewall network security barrier – UGC NET Question

A firewall acts as a barrier between a trusted internal network and untrusted external networks, inspecting traffic according to security policies. It can block unauthorised access while permitting legitimate communication, thereby reducing the risk of attacks. Firewalls may be hardware, software or a combination of both. Hence, the protective system described is a firewall.

Option A:
Option A is correct because firewall is the established term in ICT security for systems that filter network traffic based on rules.

Option B:
Option B, gateway, is a broader term for devices that connect networks and may or may not enforce security policies.

Option C:
Option C, modem, modulates and demodulates signals for communication over telephone lines or cable and is not primarily a security device.

Option D:
Option D, router, forwards packets between networks based on IP addresses but does not automatically apply security rules unless combined with firewall features.