title: Use Attribute to create Request IP constraint
body: <p>I would like to do the following (Pseudo Code):</p>
  
  <pre><code>[InternalOnly]
  public ActionResult InternalMethod()
  { //magic }
  </code></pre>
  
  <p>The "<code>InternalOnly</code>" attribute is for methods that should check the <code>HttpContext</code> request IP for a known value before doing anything else.</p>
  
  <p>How would I go about creating this "<code>InternalOnly</code>" attribute?</p>