What type of devices enforce administrative security policies by filtering incoming traffic?

Firewalls are devices specifically designed to enforce administrative security policies by controlling the flow of incoming and outgoing network traffic based on predetermined security rules. Their primary function is to examine data packets and decide whether to allow or block them based on the security settings configured by network administrators. This is crucial for protecting internal networks from unauthorized access, attacks, and other security threats.

By analyzing each packet and enforcing access control policies, firewalls create a barrier between trusted internal networks and untrusted external networks, such as the internet. This ability to filter traffic is essential for maintaining the integrity and security of a network, particularly against malicious traffic and potential attackers.

In contrast, routers primarily manage traffic between different networks, making routing decisions based on IP addresses, rather than enforcing specific security policies. Switches operate at the data link layer to direct data between devices on the same network but do not inherently include security filtering capabilities. Modems facilitate the connection to the internet by converting digital signals to analog (and vice versa), but they lack the advanced filtering functions of firewalls.