Which server protects web servers from attacks and can provide performance and reliability benefits?

The correct answer is Reverse Proxy.

Key Points

• In computer networks, a reverse proxy is the application that sits in front of back-end applications and forwards client (e.g. browser) requests to those applications. Reverse proxies help increase scalability, performance, resilience and security. 
• The resources returned to the client appear as if they originated from the web server itself.
• Large websites and content delivery networks use reverse proxies, together with other techniques, to balance the load between internal servers. 
• Reverse proxies can keep a cache of static content, which further reduces the load on these internal servers and the internal network. 
• It is also common for reverse proxies to add features such as compression or TLS encryption to the communication channel between the client and the reverse proxy.