title: Rails server runs, but not all browsers actually show the page
body: <p>I'm developing a Rails 4 app on Mac OS 10.6.8, and yesterday I started getting errors -- but only in certain browsers, and for certain URLs.</p>
  
  <p>Everything looks fine in the Terminal:</p>
  
  <pre><code>$ rails s
  =&gt; Booting WEBrick
  =&gt; Rails 4.0.1 application starting in development on http://0.0.0.0:3000
  =&gt; Run `rails server -h` for more startup options
  =&gt; Ctrl-C to shutdown server
  [2014-02-24 12:43:47] INFO  WEBrick 1.3.1
  [2014-02-24 12:43:47] INFO  ruby 2.0.0 (2013-06-27) [x86_64-darwin10.8.0]
  [2014-02-24 12:43:47] INFO  WEBrick::HTTPServer#start: pid=41543 port=3000
  </code></pre>
  
  <p>But <code>http://0.0.0.0:3000/</code> in Chrome or Safari produces a 403 error:</p>
  
  <pre><code>403 Forbidden
  hefishkUtZiafopyoshGeOnnIbDoufye
  </code></pre>
  
  <p>That address opens in Firefox, though.</p>
  
  <p>I also tried another address, <code>http://localhost:3000/</code>. Previously, Chrome displayed "No data received" with a frowny face and two buttons, "Reload" and "More". Now it works fine in Chrome. It also works in Safari and Firefox.</p>
  
  <p>Opening <code>http://127.0.0.1:3000</code> works in Chrome, Safari and Firefox.</p>
  
  <p>This is more of a bump in the road than a blockade, but its randomness is troubling. I don't think I substantially changed my Rails app in the meantime. I even created a new Rails project and got the same error messages.</p>
  
  <p>Also, I've seen other questions on SO where all three addresses suddenly don't work, and just as suddenly start working again later. I'd like to know if there's a better fix than just waiting.</p>
  
  <p>Any help would be very much appreciated.</p>