Reverse proxy

Apache HTTP Server
The Apache HTTP Server, commonly referred to as Apache, is web server software notable for playing a key role in the initial growth of the World Wide Web.

DeleGate (networking)
DeleGate is a lightweight proxy server.

nginx
nginx (pronounced “engine-x”) is a lightweight, high-performance Web server/reverse proxy and e-mail (IMAP/POP3) proxy, licensed under a BSD-like license.

Perlbal
Perlbal is a Perl-based reverse proxy load balancer and web server.

Pound (networking)
Pound is a lightweight open source reverse proxy program suitable to be used as a web server load balancing solution.

Reverse proxy
In computer networks, a reverse proxy is a type of proxy server that retrieves resources on behalf of a client from one or more servers.

Squid (software)
Squid is a proxy server and web cache daemon.

Tinyproxy
Tinyproxy is a HTTP proxy server daemon for POSIX operating systems.

Traffic Server
The Apache Traffic Server (TS) is a modular, high-performance reverse proxy and forward proxy server, generally comparable to Nginx and Squid.

Varnish (software)
Varnish is an HTTP accelerator designed for content-heavy dynamic web sites.

WinGate
WinGate is an Integrated Gateway Management system for Microsoft Windows, providing firewall and NAT services, along with a number of integrated proxy servers and also email services (SMTP, POP3...