thttpd is a simple, small, portable, fast, and secure HTTP server.

  - Simple: It handles only the minimum necessary to implement HTTP/1.1.

  - Small: It also has a very small run-time size, since it does not fork
    and is very careful about memory allocation.

  - Portable: It compiles cleanly on SunOS 4.1.x, Solaris 2.x, BSD/OS 2.x,
    Linux 1.2.x, and OSF/1 (on a 64-bit Alpha).

  - Fast: In typical use it's about as fast as the best full-featured
    servers (Apache, NCSA, Netscape).  Under extreme load it's much faster.

  - Secure: It goes to great lengths to protect the web server machine
    against attacks and breakins from other sites.

It also has one extremely useful feature (URL-traffic-based throttling) that
no other server currently has.

WWW: http://www.acme.com/software/thttpd/