Reverse Proxy

A reverse proxy represents the server side of a connection. Clients believe they are talking to a single service, but the reverse proxy is really in front, distributing requests to backend servers behind it. It is the counterpart to a forward proxy: the forward proxy hides clients from servers, while the reverse proxy hides servers from clients. Common examples include Nginx, HAProxy and the edge of most large websites.

Incoming requests hit the reverse proxy, which decides which backend should answer, then relays the response. Along the way it commonly terminates TLS, balances load across servers, caches responses, and shields backends from direct exposure. It often records the client's real address in an X-Forwarded-For header so the backend can still see who called. Because it fronts infrastructure rather than users, it is an operational tool for site owners, not a privacy tool for browsing.

s4m provides forward proxies and a VPN for masking your own outbound traffic — not reverse-proxy hosting for publishing services. The two are unrelated jobs, so if you need to sit a reverse proxy in front of your own app, that is separate infrastructure. Where s4m fits is the client side: routing your requests through an authenticated datacenter proxy so the sites you reach see an s4m exit IP instead of your origin.