A proxy server is used to manage web traffic, enhance security, and improve performance by caching frequently accessed content. It acts as an intermediary between end users and the websites they visit. On the other hand, a DNS server is primarily used for resolving domain names to IP addresses. A DHCP server is responsible for dynamically assigning IP addresses to clients on a network. Lastly, a firewall is a network security device that monitors and controls incoming and outgoing network traffic based on predetermined security rules, but it doesn’t cache contents.