Apache - The Apache project has been organized in an attempt to answer some of the concerns regarding active development of a public domain HTTP server for UNIX. The goal of this project is to provide a secure, efficient and extensible server which provides HTTP services in sync with the current HTTP standards.

aolserver - is a web server which can be configured with a web browser. It is fully integrated with aolpress, a HTML WYSIWYG Editor.

Netscape Server - Netscape offers a range of server software for setting up Internet or intranet sites or building networked applications - including Web, proxy, mail, and news servers.

phttpd - A freely available multithreaded WWW server for systems running Solaris 2.4 (or newer) which uses features like dynamic linking and memory mapped I/O (mostly I :-) to be *fast*. phttpd (Site #2) phttpd (Site #3)

roxen - is a powerfull and robust web server. It supports HTTP 1.1 and uses a browser for it's configuration. It also supports proxy-caching.

Squid Project - a high-performance proxy caching server for web clients, supporting FTP, gopher, and HTTP data objects. Unlike traditional caching software, Squid handles all requests in a single, non-blocking, I/O-driven process.

W3C httpd - a generic public domain full-featured hypertext server which can be used as a regular HTTP server.

WN - is a server for the Hypertext Transfer Protocol (HTTP). Its primary design goals are security and flexibility. One of its objectives is to provide functionality usually available only with complex CGI scripts without the necessity of writing or using these scripts.

XS-HTTPD 2.2 - A very small and fast WWW server! What's more, it's free!