Pound

REVERSE-PROXY AND LOAD-BALANCER

The Pound program 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 - no warranty, it's free to use, copy and give away.

WHAT POUND IS:

• a reverse-proxy: it passes requests from client browsers to one or more back-end servers.
• a load balancer: it will distribute the requests from the client browsers among several back-end servers, while keeping session information.
• an SSL wrapper: Pound will decrypt HTTPS requests from client browsers and pass them as plain HTTP to the back-end servers.
• an HTTP/HTTPS sanitizer: Pound will 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.
• a request redirector: requests may be distributed among servers according to the requested URL.

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.

http://www.apsis.ch/pound/