Firefox Addon to override system name resolution for certain host names?

Question

Is there any Firefox plugin that allows to change how Firefox perform name resolution? I want to override the system-wide hostname resolver to attach some IP to certain hostnames.

Let me explain. Let's say I'm developing a new website and I want to test using the actual hostname but my site is run by a local webserver, I'd like to do this:

System-wide resolver: www.domain.com ---> 10.20.30.40
Ovveride by addon:    www.domain.com ---> 127.0.0.1

Is there anything like this? Thank you.

Answer 1

You don't even need a plugin to do that. You can do it with the proxy settings. Specifically, you can use the proxy auto-configuration option with a PAC file that you create. The PAC file is written in javascript. For you it might look something like this:

function FindProxyForURL(url, host) {
    if (host=='www.domain.com'){
        return 'PROXY 127.0.0.1:80';
    }
    // All other domains should connect directly without a proxy
    return "DIRECT";
}

Save this as my-proxy.pac file and point the proxy auto-configuration at it.

For more information on proxy autoconfiguration, see wikipedia: http://en.wikipedia.org/wiki/Proxy_auto-config