Is there a way to block chrome or firefox from accessing anything located at localhost?

I built my web application on top of a LAMP stack @ localhost and it's kind of big (for me) and I would like to test it, but when I access site.com it loads all the resources that are linked on http://localhost/ because they are on my machine but it doesnt load those resources when I try to access the website from another computer.

So, I need to test the application and it would be nice to just block localhost completely.

A workaround I found was using a proxy addon in firefox and blacklisting http://localhost/* but it's extremely slow because the proxies are free.

So I would like to find a way to just block localhost completely in any of these browsers and that would make my life much easier.


Reading your post I got the impression that the website you are building uses absolute URLs to http://localhost/some.html If this is true, please fix your application to use relative URLs like some.html or /site.html.

If my impression was wrong and you still want to block localhost from your browser, you could misuse the "proxy auto-config" feature in your browser. Save the following into a local file (say, ~/proxy.pac):

function FindProxyForURL(url, host)
  if (isInNet(host, "", ""))
    {return "PROXY";}
  if (dnsDomainIs(host, "localhost"))
    {return "PROXY";}
    {return "DIRECT";}

In Firefox, go to Preferences/Advanced/Network/Connection Settings... Choose "Automatic proxy configuration URL" and specify the full path for the saved file. The browser will try to use a SOCKS proxy at that does not exist and will fail reading any local files through http or https.

  • It looks like the latest Firefox ignores the proxy configuration for localhost. – Mikalai Daronin Jun 18 '19 at 10:06

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