What is the function of the "Web Application Firewall" feature?

The function of the "Web Application Firewall" feature is primarily to protect web applications by filtering and monitoring HTTP traffic to and from a web service. This involves analyzing the incoming and outgoing web traffic for signs of malicious activity or attempts to exploit vulnerabilities, allowing the firewall to apply rules and policies designed to block potentially harmful requests. By focusing on common web application attacks such as SQL injection, cross-site scripting (XSS), and other vulnerabilities, the Web Application Firewall acts as a protective layer that secures web applications from various threats while ensuring that legitimate traffic is efficiently allowed through.

The other options focus on different functions that may be relevant in a network context but do not describe the specific role of a Web Application Firewall. Enhancements in performance through caching, antivirus functions for general web traffic, or role-based access limitations are not the core objectives of a Web Application Firewall. Thus, the choice that highlights the protection and monitoring of HTTP traffic is the most accurate representation of the function of this feature.