>>>> 1. Use de WPAD protocol: lets say PROXY squid1; PROXY squid2 >>>> (this is fail over) IMHO, using PAC (with or without WPAD) is the simplest and most effective approach to failover, requiring no additional software beyond a web server to host the PAC file. With PAC, the browser will automatically switch to the second proxy in the list if the first stops responding. All modern graphical browsers support PAC, and nearly all support WPAD. The PAC script is very powerful, you can use many, but not all, Javascript string and numeric functions. With a little effort you can have PAC distribute user load across multiple proxy servers, or even hash the request URL so, for example, all requests for dilbert.com first go to squid1, to get the most value from cached content. For more on PAC, see http://wiki.squid-cache.org/Technology/ProxyPac
