title: Accept requests only from a specific host
body: <p>I'd like to filter out requests coming from blacklisted hosts. I did some research but found nothing reliable (using RemoteIp, for instance, or UserHostAddress).</p>
  
  <p>Let's say my service receives requests from several products. Example:</p>
  
  <p>GET /ping only from ["<a href="https://producta.com" rel="nofollow">https://producta.com</a>"]</p>
  
  <p>Product A on <a href="https://producta.com/" rel="nofollow">https://producta.com/</a> - ok</p>
  
  <p>Product B on <a href="https://anotherurlforb.com" rel="nofollow">https://anotherurlforb.com</a> - forbidden</p>
  
  <p>Is this feasible?</p>
  
  <p>(I'm currently using ServiceStack and I'm loving it.)</p>