W3C httpd is a generic public domain full-featured hypertext server
which can be used as a regular HTTP server. The running typically on
port 80 to serve hypertext and other documents, and also as a proxy --
a server on a firewall machine -- that provides access for people
inside a firewall to the outside world. When running as proxy httpd
may be configured to do caching of documents resulting in faster
response times.

Homepage:
https://www.w3.org/Daemon/
