title: Check if cookie does NOT contain specified content NGINX
body: <p>There are countless tutorials on checking if a cookie exists and contains my content, in this case <code>foobar</code>.</p>
  
  <p>How do I do the following assuming mycookie is the cookie that I want set.</p>
  
  <pre><code>if ($cookie_mycookie does not equal "foobar") {
    return 401;
  }
  </code></pre>
  
  <p>I have tried the following to no avail.</p>
  
  <pre><code>if (!$http_mycookie ~* "foorbar" ) {
    return 401;
  }
  </code></pre>
  
  <p>Thank you!</p>