Apache HTTP Server

Apache HTTP Server, usually called httpd, is a web server maintained by The Apache Software Foundation. The documentation describes it as a server for modern operating systems, and its modules add reverse proxying through mod_proxy and load balancing through mod_proxy_balancer. On Unix the program runs as a daemon that keeps running in the background to handle requests. The project publishes source code; the installation guide covers building it on Unix-like systems, and operating system distributions ship their own packages.

Worth knowing

The daemon model means a host has to allow a long-running server process, not only static files. The 2.2 line is end-of-life; the 2.4 line is the current one.