Pound is a reverse proxy, load balancer and HTTPS front-end for Web server(s). Pound was developed to enable distributing the load among several Web-servers and to allow for a convenient SSL wrapper for those Web servers that do not offer it natively. Pound is distributed under the GPL license.
Pound is a very small program, easily audited for security problems. It can run as setuid/setgid and/or in a chroot jail. Pound does not access the hard-disk at all (except for reading the certificate file on start, if required) and should thus pose no security threat to any machine.
Pound is set to have performed well in large volums of upto 30M connections per day with over 600 requests/second at peak.
Pound functions as a ,
Reverse-Proxy: Passes requests from client browsers to one or more back-end servers.
Load Balancer: Distribute the requests from the client browsers among several back-end servers, while keeping session information.
SSL wrapper: Decrypt HTTPS requests from client browsers and pass them as plain HTTP to the back-end servers.
HTTP/HTTPS sanitizer: Verify requests for correctness and accept only well-formed ones.
a fail over-server: should a back-end server fail, Pound will take note of the fact and stop passing requests to it until it recovers.
Request Redirector: requests may be distributed among servers according to the requested URL.
Pound can also support Virtualhosts. Pound however is not a Webserver or a Web-accelerator or a proxy server.
Pound work with a variety of Web servers, including Apache, IIS, Zope, WebLogic, Jakarta/Tomcat, iPlanet, etc. In general Pound passes requests and responses back and forth unchanged, so we have no reason to think that any web server would be incompatible.
Client browsers that were tested:
IE 5.0/5.5 (Windows) HTTP/HTTPS
Netscape 4.7 (Windows/Linux) HTTP/HTTPS
Mozilla (Windows/Linux) HTTP/HTTPS
Konqueror (Linux) HTTP/HTTPS
Galleon (Linux) HTTP/HTTPS
Opera (Linux/Windows) HTTP/HTTPS
Lynx (Linux) HTTP
For more information, download, installation procedures and samples of different configurations can be found here