title: ASP.net - Restrict user login to a specific machine
body: <p>Please provide your suggestions on how to restrict a user login to a specific machine for an ASP.net Website.</p>
  
  <p>In other words, the requirement is deploy a simple yet effective <strong>2 factor authentication</strong>.</p>
  
  <p><em>The aim is allow access to employees only from the company workstations. This should be applicable to all company branches and authenticated from a central server application.</em></p>
  
  <p>After a lot of searching and scrolling the WWW, i am left pondering upon these 2 solutions:</p>
  
  <ol>
  <li><a href="http://support.microsoft.com/kb/315588" rel="nofollow">Microsoft Client Side Certificates</a></li>
  <li><a href="http://www.rsa.com/node.aspx?id=1156" rel="nofollow">RSA SecurID</a></li>
  </ol>
  
  <p><strong>Please provide your valuable suggestions on <em>CON's</em> of these methods OR <em>better alternatives</em>.</strong></p>