Fail over mechanism // Ip forwarder

[Bob Sauvage]

Hello world !

 I have a web application server (tomcat, jboss,...) and I want to put in place a simple fail over mechanism. I see that as a " ip forwarders". 

 I mean when a client want to acces our application, he arrives on a server who redirects him on the ip address of the web application server and if this server is down, it redirects him on the backup web application server. 

 I have the idea but not the sufficient knowledge... Can you give me a tips or a track ?

 Thanks a lot !