Provides processing of multiple (thousands) simultaneous connections to hundreds of distributed service instances without risking system's stability.

Allows you to organize a highly available environment and is capable of:

• route HTTP requests depending on statically assigned cookies
• spread the load among several servers while assuring server persistence through the use of HTTP cookies
• switch to backup servers in the event a main one fails
• accept connections to special ports dedicated to service monitoring
• stop accepting connections without breaking existing ones
• add/modify/delete HTTP headers both ways
• block requests matching a particular pattern

Home page: http://www.haproxy.org/