A home user has purchased a subscription for a service that blocks malicious sites by preventing them from resolving correctly. Which of the following settings most likely needs to be changed on the user's router to enable this functionality?

Port forwarding is a technique used to allow external devices to access services on a private network by forwarding specific ports. This setting does not relate to blocking malicious sites; instead, it is typically used for gaming, remote access, or web hosting. Changing port forwarding will not enable the functionality of blocking harmful site resolutions.

A perimeter network is a secure area that separates an internal network from external networks, often used to host external-facing services. While it enhances security, altering this setting does not directly affect how DNS requests are processed or how malicious sites are blocked.

Universal Plug and Play (UPnP) facilitates automatic discovery and configuration of devices on a network. While it may aid in easy connectivity, it is not related to DNS resolution or the blocking of malicious sites.

The DHCP server assigns IP addresses to devices on the network, ensuring they can communicate. Although it plays a crucial role in network management, changing DHCP settings does not influence the resolution of domain names or the ability to block harmful sites.