title: Allow IP address without authentication
body: <p>I have set up a site that is currently work in progress. I'm using an external SMS gateway that needs access to a script on my server. However, I have set up a basic username and password authentication for regular users, but the SMS gateway can't get through that.</p>
  
  <p>How can I allow a single IP to pass through the authentication without authenticating itself, and deny all other users that aren't authenticated?</p>
  
  <p>Here's my <code>.htaccess</code> file:</p>
  
  <pre><code>Order allow,deny
  Allow from all
  AuthType Basic
  AuthUserFile /www/.site_htpasswd
  AuthName "Protected Area"
  require user admin
  </code></pre>