What describes an intercepting proxy?

• A. A tool that lets you analyze and modify any request, and any response exchanged between an HTTP client and a server
• B. A firewall that blocks all outgoing traffic
• C. A DNS resolver
• D. A tool for caching web content

Answer: (A)

An intercepting proxy sits between the client and the server and mediates every HTTP request and response. It captures the traffic in real time, letting you inspect details like headers, parameters, and body content, and crucially, modify them before the request reaches the server or before the response returns to the client. This live editing capability is what makes it a powerful tool for security testing—you can alter inputs, test how the application handles unexpected data, and then forward the changed traffic to observe how the server reacts. Tools like Burp Suite or OWASP ZAP operate this way.

It’s not simply a firewall that blocks traffic, nor a DNS resolver, nor primarily a caching tool. A firewall blocks or permits traffic, a DNS resolver translates domain names to IPs, and while some proxies can cache content, that caching behavior isn’t what defines an intercepting proxy—the defining feature is the ability to intercept and modify traffic in transit.