title: Make back end APIs only accessible via Azure API management
body: <p>I have multiple Web APIs deployed in Azure without applying authentication, so anyone has access to internet has the access to the Web APIs. </p>
  
  <p>Now I would like to apply authentications to the Web APIs, instead of implementing the same authentication logic in different Web APIs, I found Azure API gateway (API management) is a potential solution. </p>
  
  <p>With Azure API management documentation, I learned I can apply policies like <code>validate-jwt</code> to authenticate requests to back end Web APIs. However, endpoints of the back end Web APIs are still available to users. </p>
  
  <p>So, how should I hide them? Must I define a sub network or does Azure API management have a feature for this?</p>