Reverse proxy

In computer networks, a reverse proxy or surrogate server is a proxy server that appears to any client to be an ordinary web server, but in reality merely acts as an intermediary that forwards the client's requests to one or more ordinary web servers.^[1][2] Reverse proxies help increase scalability, performance, resilience, and security, but they also carry a number of risks.

Companies that run web servers often set up reverse proxies to facilitate the communication between an Internet user's browser and the web servers. An important advantage of doing so is that the web servers can be hidden behind a firewall on a company-internal network, and only the reverse proxy needs to be directly exposed to the Internet. Reverse proxy servers are implemented in popular open-source web servers, such as Apache, Nginx, and Caddy. Dedicated reverse proxy servers, such as the open source software HAProxy and Squid, are used by some of the biggest websites on the Internet.

A reverse proxy can track all IP addresses making requests through it and it can also read and modify any non-encrypted traffic and risks logging passwords or injecting malware if compromised by a malicious party.

Reverse proxies differ from forward proxies, which are used when the client is restricted to a private, internal network and asks a forward proxy to retrieve resources from the public Internet.