What service is responsible for managing permit and deny policies that need periodic review to remove unused entries?

The correct choice focuses on firewalls, which serve as a critical line of defense in network security. Firewalls manage traffic entering and exiting networks based on predetermined security rules. These rules include permit and deny policies that specify which types of traffic are allowed or blocked.

Regular review and maintenance of these policies are essential for several reasons. Over time, as network configurations and usage patterns change, certain rules may become obsolete or no longer necessary. By periodically reviewing these entries, organizations can ensure that their firewall remains efficient and effective, minimizing the risk of security breaches while also optimizing performance.

In contrast, the other services mentioned do not primarily handle security traffic management in this way. DNS (Domain Name System) is responsible for translating domain names into IP addresses, enabling resource identification on the internet. DHCP (Dynamic Host Configuration Protocol) automates IP address assignment for devices on a network but does not manage security policies. Active Directory is primarily a directory service for managing users and computers in a network environment rather than controlling traffic flow or security enforcement.