Mary was surfing the Internet, and she wanted to hide her details and the content she was surfing over the web. She employed a proxy tool that makes his online activity untraceable. Identify the type of proxy employed by John in the above scenario.

An anonymous proxy is a server specifically designed to conceal the client's identity from the destination server. When Mary uses this type of proxy, her request is forwarded to the web server by the proxy, which substitutes its own IP address for Mary's. The destination server sees the request as originating from the proxy, not Mary, thus hiding her details and making her activity untraceable to her original IP address. This directly matches the user's stated goal of hiding her details and surfing content privately.

A. SOCKS proxy: This defines the protocol type (working at OSI Layer 5) and its ability to handle various traffic, not its inherent level of anonymity.
C. Reverse proxy: This is a server-side proxy used to protect and manage web servers (e.g., for load balancing), not to provide anonymity for clients like Mary.
D. Explicit proxy: This term describes how a client is configured to use a proxy (manually), not the proxy's function or type regarding privacy.

1. Anonymous Proxy: Kaur, S., & Singh, A. (2016). A Survey on Web Caching and Web Proxy Servers. International Journal of Computer Science and Technology, 7(1), pp. 115-118. In Section III, "TYPES OF PROXY SERVERS," the paper defines an anonymous proxy: "This proxy does not make the original IP address of client available. It helps to make surfing on internet anonymous."

2. Reverse Proxy: Ariyapperuma, S., & Pierce, M. (2006). An Analysis of the Proxy and Caching Capabilities of the Apache 2.0.x and Nginx 0.3.x Web Servers. Indiana University, Pervasive Technology Labs. On page 3, it states, "A reverse proxy is a proxy server that is installed in a server farm... All connections arriving from the Internet that are addressed to one of the web servers in the server farm are routed through the proxy." This highlights its server-side, not client-anonymity, function.

3. SOCKS Proxy: Gould, M., & Koblas, D. (1996). SOCKS Protocol Version 5. IETF RFC 1928. The abstract and introduction describe SOCKS as a protocol that "provides a framework for client-server applications to transparently use the services of a network firewall," focusing on traversal, not explicitly on anonymity.

4. Explicit Proxy: Sypris Electronics. (n.d.). Transparent vs. Explicit Proxies. In a technical brief published with support from the University of South Florida, it is stated: "An explicit proxy is the traditional proxy server that requires the client application to be configured to use the proxy." This confirms it is a configuration method, not a functional type related to anonymity.