What does a Web Application Firewall (WAF) primarily monitor and filter?

A Web Application Firewall (WAF) is designed specifically to monitor and filter the traffic between web applications and the external world, primarily focusing on HTTP and HTTPS conversations. This specificity allows the WAF to protect web applications from a range of application-layer attacks, such as cross-site scripting (XSS), SQL injection, and other vulnerabilities that can be exploited through web protocols.

By operating at the application layer, a WAF can analyze the content of the web traffic, ensuring that only legitimate requests are allowed while blocking malicious activity. This targeted approach provides enhanced security for web applications, as it can distinguish between normal and anomalous behavior based on the application’s expected requests and responses.

The other options relate to different areas of network security and do not align with the specific functionality of a WAF. For instance, monitoring network traffic is broader and encompasses various protocols beyond those utilized by web applications, while email communications and data storage access pertain to different security domains altogether. Therefore, focusing on HTTP and HTTPS conversations accurately captures what a WAF is designed to filter and protect.